Chapter 15 Rendering
From ShadeCamp
Objects you create are rendered and displayed as images according to the current settings of lights, backgrounds, Cameras, and Motions. In this chapter, we will take a look at the Image window and the rendering settings.
The Image Window
In the Image window, you can display the rendered image, and watch the image being rendered, as well as adjust the rendering settings. Select Image Window from the View menu to open the Image window.
The diagonal lines appear in the Image window (if there is no existing image) to show the specified image size.
Rendering
Click the Render button in the Image window, or select Render or Render All from the Rendering menu to start rendering a new image. You can also begin rendering by selecting Render from the contextual menu displayed using the right click (Win) / Ctrl key and click (Mac) in the Image window. While rendering an image, objects are rendered line by line from the top of the Image window if the Scan Line technique is used. When the Ray Tracing or Path Tracing technique is used, first a pre-process called space sharing is performed, and then objects are displayed. The screen is divided into large blocks, consisting of dozens of pixels horizontally and vertically, and scanned by a block cursor. Then the screen is divided into smaller blocks, several pixels by several pixels in size, and is scanned by the block cursor in the same way. This process is repeated several times until the final rendering is displayed. While the rendering process is continuing, the Rendering Indicator rotates. The elapsed time of the rendering task is shown at the top of the window, just to the right of the buttons. Clicking the Render button in the Image window while holding down the Shift key will render all objects without changing the current object selection state.
Rendered Objects
By default, only the selected objects are rendered. In addition, you can keep certain objects from being rendered as follows:
Using the Suppress Rendering Character
Rendering of an object or part can be disabled by preceding the name of that object or part (displayed in the Browser window) with the Suppress Rendering character, #. This character is also effective for quick rendering and Radiosity.
Using the Render Checkbox in the Browser Window
Objects or parts for which the Render checkbox is off in the Browser window will not be rendered in the Image window. Child objects or parts of a parent object or part for which the Render checkbox is off will also be excluded from the rendering. This is true for the Radiosity calculation as well. The Rendering Options can be displayed by clicking the Show/Hide triangle button in the Image window.
Cancelling Rendering
Click the Stop button in the Image window to cancel rendering.
Cancelled rendering can be resumed. You can also resume rendering an image whose rendering was cancelled the next time the Scene File is opened.
Resuming Rendering
Click the Resume button in the Image window to resume rendering.
The rendering results will be undefined if the Rendering Settings have been altered.
Saving an Image
To save the rendered image to a file, click the Save button in the Image window.
The file types in which you can save images are as follows:
•Bitmap file (.bmp)
•PICT file (.pct)
•GIF (.gif)
•Targa file (.tga)
•Raw file (.raw)
•Shade Image file (.shdimg)
•TIFF file (.tiff)
•PNG (.png)
•HDR (.hdr)
•PFM (.pfm)
•PSD (.psd)
•OpenEXR (.exr)
•Flash (.swf)
In addition to the above listed files, .SGI, 8BPS, BMPf, JPEG, MIFF, PNGf, PNTG, TPIC, and qtif can be saved via Apple QuickTime.
Merging a Background Image
To merge the rendered image with a background image from another file, click the Merge button. A dialog box for loading a background image will appear. Open a file to be merged with the background of the Image window. The function of the Merge button is identical to that of the Backdrop checkbox in the Rendering Options.
Note: Refer to the “Merging with a Background” section, for more details on merging with a background image.
Zooming In and Out
You can change the scale for viewing the image without changing the size of the Image window. The view scale can be changed by clicking the + button or - button of the Scale in the Image tab of the Rendering Options. One click increases or decreases the scale one level. When you click the button with the Ctrl Key (Win) / Option key (Mac) pressed, the scale will be doubled, like x1, x2, x4, and x8. Clicking with the Shift key restores the actual view size (x1) regardless of + button or - button.
You can also change the scale by performing the following operations in the Image window:
•The mouse pointer will change to the zoom-out pointer when pressing the Space and Ctrl or Z key (Win) / Space and Option key (Mac) on the image. With the pointer displayed, when you click the image itself, the scale will be decreased by one level.
•The mouse pointer will change to the zoomin pointer when pressing the Space and X key (Win) / Space and }{ key (Mac) on the image. With the pointer displayed, when you click the image itself, the scale will be increased by one level.
Scrolling the Image
You can scroll an image to large to fit in the Image window.
To scroll the image, use the scroll bars of the Image window. You can also use the mouse pointer, which changes into a hand-shaped pointer when the Space bar is held down on the image. Dragging the image with this pointer will scroll the view area of the image.
Rendered Image Size
The size of the image to be rendered can be adjusted by typing appropriate value in the Width and Height text boxes in the Image tab of the Rendering Options, or by holding the Shift key down while dragging the borderline or the corner (Win) / dragging the size box of the Image window (Mac).
The Image tab of the Rendering Options provides a few more functions.
Note: If you drag the borderline or the corner (Win) / the size box (Mac) of the Image window without holding down the Shift key, the size of the Image window will change, while the size of the image to be rendered won’t.
Rendering Options: Image
Open the Rendering Options and choose the Image tab.
Width and Height Text Boxes
The width and height in pixels of the image to be rendered can be set here.
Scale: - Button and + Button
One click increases or decreases the view scale by one level. Changing this scale does not affect the size of the Image window.
Pixel Ratio Text Box
The pixel ratio of the rendered image is shown here. This setting can be changed when rendering an image to be output on a device whose pixel ratio is not 1.0. In this case, it needs to be set together with the image size.
Pixel Ratio of 0.9
Pixel Ratio of 1.0
Result of Pixel Ratio 1.2
Area Rendering
You can also render just a portion of the Image window. Drag to select an area in the Image window while holding down the Ctrl or Z key (Win) / Option key (Mac) to render the selected area.
Drag to select an area in the Image window while holding down the Shift + (Ctrl or Z key) (Win) / Shift + Option key (Mac) to render all objects in the selected area.
Drag to select an area to render while holding down the Shift + (Ctrl or Z key) (Win) / Shift + Option key (Mac).
The dragged area is cleared in preparation for rendering.
During Rendering
Completed Rendering
Rendering Options
Various options for rendering are specified in the Rendering Options. The Rendering Options can be shown or hidden by clicking the Show/Hide button in the Image window. In the Rendering Options, there are five tabs (Basics, Image, GI, Effects, MultiPass, and Misc.) to switch setting items.
Rendering Options
Rendering Style Menu
This pull-down menu allows you to add, remove or save as default the current Rendering Options. When you select the Add option from the pull-down menu, a dialog box appears where you can enter the name for the settings to be saved. A default name is displayed in the dialog box, which you can use to save the settings. Selecting the Remove option will delete the current set of saved settings.
Rendering Method Menu
You can choose from four rendering techniques in this pull-down menu, based on your purpose and the time allowed for the rendering calculation.
Ray Tracking (Draft)
Ray Tracing (Draft) replaces the Scan Line method used in Shade 9 and earlier as a faster, higher quality preview rendering method.
Global Illumination is a rendering method that can create more realistic images by calculating various light phenomena such as reflections and shadows between shapes, refraction of transmitted light, specular reflection, caustics as well as direct light from a light source.
You can elect to turn Global Illumination on or off, however it only is available with the Radiosity option. Although this support does not correspond to Path Tracing or Photon Mapping, it can express indirect light and sky light by using Radiosity.
Ray Tracing (Draft) does not support soft shadows with Distribution Lights, Point Lights or Spot Lights. However it can create soft shadows using Shadow Maps.
Compared with Ray Tracing, Ray Tracing (Draft) has the following limitations:
- No refractions with transparent objects
- No reflections of objects
- No Global Illumination settings for Path Tracing
- No Global Illuminatino settings for Photon Mapping
Ray Tracing
Ray Tracing provides very high-quality rendering using ray casting and space sharing. It enables simulation of reflection and refraction. The Ray Tracing technique, as compared with the Path Tracing technique, cannot express roughness of reflection, roughness of transparency for refraction, correct rendering of the area generated by the area light source (light source attributes), nor the depth of field effect for the camera. Soft shadows cannot be expressed with Ray Tracing, but are available using the Shadow Map Blur. Indirect light and sky light conditions can be achieved using the Radiosity feature.
Objects rendered using the Ray Tracing method with the Render Shadows checkbox on, the type of shadow set to Ray tracing, and Regular selected in the Surface Subdivision pull-down menu. With Ray Tracing, the surface subdivision processing is not performed for spheres, which saves memory.
These objects are also rendered with Ray Tracing, but Shadow map is selected for the type of shadow. When shadow map is used, surface subdivision is carried out for every object. The result of the surface subdivision for spheres is the same as that of the Scan Line method.
Note: Shadow Maps with the Ray Tracing or Path Tracing rendering are only available in Shade 9 professional.
Path Tracing
Path Tracing provides extremely high-quality rendering using a developed Ray Tracing technique that allows you to express indirect light using global illumination. The global illumination is a rendering technique that can generate more realistic images by calculating not only direct light from the light source, but also a variety of light phenomena such as mutual reflection and shadows between objects, refraction of transmitted light, mirror reflection, and caustics. As with the case of the Distribution Ray Tracing technique provided in the earlier Shade series, the softness of shadows and the depth of field effects can be expressed and the Radiosity features are also available. However, this technique involves a huge number of calculations, and therefore requires a longer time to render, particularly for a complex scene with a large size.
Objects rendered using the Path Tracing method. This method can express effects such as softness of shadows and depth of field.
Note: Global Illumination is not set in the GI tab in the Rendering Options in the case of this image. For details on Global Illumination, refer to the “Global Illumination pull-down menu” section.
The Path Tracing method can suppress moiré patterns. From left to right: Ray Tracing with anti-aliasing off, Ray Tracing with anti-aliasing on, and Path Tracing, displayed at low resolution to emphasize the effects.
Note: Shadow Maps with Ray Tracing or Path Tracing rendering are only available in Shade 9 professional.
Wireframe
This method renders an object as a wireframe. It uses a process called “Hidden Line Removal” (the wireframe or planes in the back are hidden behind the front surface), and “Depth Cue” (the brightness of the wireframe or surface is gradually changed with depth), as well as the Anti-aliasing process. The wireframe corresponds to the borderlines of the subdividing surface when Flat Shading is performed with the Scan Line method. Care must be taken since the wireframe displayed in the Figure window looks different for curved surfaces. Surface subdivision and Anti-aliasing settings are made in the Rendering Options, while the other settings are made in the dialog box that will appear by clicking the Set… button.
An image rendered using Wireframe, with the line color set to the diffuse color of the object, Hidden Line Removal on, Paint Color set to gray, and Depth Cue checkbox on.
Wireframe rendering has the following limitations:
•Boolean rendering is not supported. Perform the Boolean modeling first, then render using Wireframe.
•The Hole checkbox of the Object Info for line objects is not supported.
•The real color cannot be generated.
Set… Button
When Wireframe or a renderer plug-in is selected in the Rendering Method pull-down menu, clicking this button displays a dialog box for the settings.
Wireframe Options Dialog
With Wireframe selected in the Rendering Method pull-down menu, click the Set… button to display the Wireframe Option dialog box. This is used for Wireframe rendering settings.
Use Diffuse Color Checkbox
With this checkbox on, the Diffuse color specified in the Surface window is used as a color to render the wireframe. If the Diffuse color is not specified, or this checkbox is off, the color specified in the Color box is used.
Color Box
When the Use Diffuse Color checkbox is off, or the Diffuse color is not specified in the Surface window, the color specified in this color box is used to render the wireframe. Clicking this color box will display a color picker.
Width Pull-down Menu
You can choose from 1 to 10 pixels for the width of the wireframe.
Background Color Box
Used to set the background color. Clicking this color box will display a color picker.
Use Checkbox
With this checkbox on, the Hidden Line Removal process, where the wireframe and planes in the back are hidden behind the front surface, is used to facilitate understanding of the object position.
Use Paint Color Checkbox
When this checkbox is on, planes are painted in the color specified in this color box. The Alpha channel is also painted.
Paint Color Box
Used to set the paint color. Clicking this color box will display a color picker.
Depth Cue Checkbox
When this checkbox is on, the Depth Cue process, where the brightness of the wireframe or surface is gradually decreased with depth, is used to express the depth of the objects.
Software Renderer
When this checkbox is on, the wireframe is drawn without using the hardware accelerator. If the result of Wireframe rendering is abnormal, it may be improved by changing this setting.
Reset Button
This button restores the settings in the Wireframe Option dialog box to those in effect when it was opened.
Default Button
This button returns the settings in the Wireframe Option dialog box to the default values.
Basics Tab
Surface Subdivision Pull-down Menu
The level of surface subdivision is specified by this pull-down menu.
No Subdivision
Select this option to render objects that do not require subdivision, such as Polygon Mesh objects, when the screen contains many objects to be rendered, or when the system has limited memory resources.
Coarse
Select this option to render objects with fewer surfaces, or when the system has limited memory resources.
Regular
This is the default setting.
Fine
Select this option when the Regular option may not provide a sufficient level of subdivision, and the system has adequate memory resources.
Very Fine
Select this option when the Fine option may not provide a sufficient level of subdivision, the screen contains fewer objects, and the system has adequate memory resources.
Note: Refer to the “Subdividing Surfaces” section below, for more information on surface subdivision.
Shading Pull-down Menu
You can select from Smooth Shading or Flat Shading for Scan Line rendering. This pull-down menu is only available when Scan Line rendering is chosen.
Objects rendered with the Flat Shading option on.
Anti-Aliasing Checkbox and Pull-down Menu
This checkbox controls anti-aliasing. It is available when Smooth Shading is selected from the Shading pull-down menu for Scan Line rendering, or when Ray Tracing is chosen. Anti-aliasing is always performed in Path Tracing. Anti-aliasing reduces the quantization error observed at edges with large color contrasts. This error is also referred to as “jaggy” edges. When Ray Tracing is selected and this checkbox is on, high quality rendering and precision over-sampling are achieved.
You can set the over-sampling in this pull-down menu. When rendering using Ray Tracing, this over sampling improves the quality of anti-aliasing by adjusting the number of rays.
When you select Adaptive, the level of anti-aliasing required for each part of the objects in a rendered scene is computed and allocated automatically. This results in an optimum tradeoff between quality and speed.
Bottom: Rendered with over-sampling properly adjusted to reduce “jaggies.”
Render Background Checkbox
The background is rendered when this checkbox is on. For Scan Line rendering, this checkbox is only available when Smooth Shading is selected in the Shading pulldown menu.
Reflect Background Checkbox
The background is reflected by surfaces with reflection and/or transparency set when this checkbox is on. For Scan Line rendering, this checkbox is only available when Smooth Shading is selected in the Shading pulldown menu.
Both Render Background and Reflect Background checkboxes on.
Render Background checkbox off and Reflect Background checkbox on.
Render Background checkbox on and Reflect Background checkbox off.
Render Shadows Checkbox and Pulldown Menu
Shadows are displayed when this checkbox is on. When Ray Tracing is selected in this pull-down menu, shadows are fully generated and rendered for each pixel of the image. When Shadow map is selected, you use the group of settings that are activated below the checkbox, or for the individual light sources, to set the Shadow map.
Note: Shadow Maps with Ray Tracing or Path Tracing rendering are only available in Shade 9 professional.
This image shows the shadows generated by the Ray Tracing method. With this method, shadows become sharp.
This image shows the shadows generated using Shadow map. With this method, shadows become soft.
Shadow Map Size Text Box
The size of the Shadow Maps is entered here. Shadow Maps refer to objects casting shadows as seen from the light source; i.e., the shadows of 3-dimensional objects. Shadow Maps are created for each defined light source. The larger the map size the sharper the shadow. If the size is too small, the shadows will have a stepped (jaggy) pattern. If too large, an insufficient memory condition may occur. You can perform test renderings to find optimal values. The shadow map cannot be generated if the size value is zero. The Shadow Map Size can also be specified in the Distance Light window, the Object Info window for point lights or spotlights, and the Object Info window of line objects for area lights and linear lights. When the Shadow Map Size value is not defined in one or more of these windows, the value specified in the Rendering Options is used for those lights.
Shadow Map Bias Text Box
When a surface on which the Shadow Map is projected is not parallel to the map, the shadow map, in whole or in part, may not be displayed. By modifying the bias value, you can solve this problem. When the Shadow Map Bias value is not defined in a light-related window, the value specified in the Rendering Options is used.
Shadow Map Blur Text Box
The outlines of Shadow Maps will be blurred according to the value entered in this field. When the Shadow Map Blur value is not defined in a light-related window, the value specified in the Rendering Options is used.
Sampling Pull-down Menu
Used to specify the sampling number for the Shadow Map. Higher values may increase the rendering time, while lower values may cause flicker in animations.
1. An image rendered with all the values in the Shadow Map text boxes set to the defaults, i.e. Size: 512; Bias: 1.0; Blur: 1.0, and one Infinite Distant Light Source. Note that the shadows of the columns are not sharp and no shadows are rendered for the pots.
2. To sharper the outlines of the column shadows, increase the Shadow Map Size. The results of our experiments show that a value of 2048 is sufficient to render crisp outlines. The shadows of the two pots may be correctly rendered by adjusting the Bias value, judging from the pixel size of the column shadows.
When the Map Size is set to 64, virtually no shadows can be seen.
3. When the Bias is set to 0, the shadows of the pots seem to be most clearly rendered. Our final settings here are: Size: 2048; Bias: 0; Blur: 1.5.
A scene rendered with two Point Lights and no Infinite Distance Light Source. The Point Lights are placed above the two columns, to keep them outside of the Camera view. Since the light sources are close to the objects, a Shadow Map Size of 150 is sufficient. The Bias and Blur values are 0.01 and 1, respectively.
The example above was rendered using the Ray Tracing technique. The shadow edges are extremely sharp.
A revised version of the first example from the previous page (Step 1). Point Lights were added and the color and brightness settings of the lights were modified. The Shadow Map settings are the same as the first example.
The example above was rendered using the Ray Tracing technique.
Image Tab
Width and Height Text Boxes
Scale: - Button and + Button
Pixel Ratio Text Box
Refer to the “Size of Rendered Image” section for details on the above items.
Backdrop Checkbox
When this checkbox is on, the background image loaded into the Picture Box is merged with the background of the rendered image on completion of the rendering.
The function of this Backdrop is identical to that of the Merge button.
Width and Height Text Boxes
Used to show the background image size in pixels.
The size of this image is 300 x 175 pixels, which fits with the background image whose size is also 300 x 175 pixels.
If you make the rendered image size 400 x 300, the background image is too small.
Picture Box
Used to load and display the background image. Use the contextual menu in this Picture box to load an image.
G.I. Tab
Global Illumination Pull-down Menu
Select None, Path Tracing, Photon Mapping, or Radiosity for the global illumination method.
This pull-down menu is effective when Ray Tracing or Path Tracing is selected. For the Scan Line method, the Radiosity result is available only in Shade 10 professional.
For details on Radiosity, refer to Chapter 16: Radiosity.
Path Tracing Settings
The Path Tracing settings are enabled when Path Tracing is selected from the Global Illumination pulldown menu.
Image rendered with Path Tracing and Global Illumination set to Path tracing.
Photon Mapping Settings
The Photon Mapping Settings are enabled when Photon Mapping is selected from the Global Illumination pull-down menu.
Number of Photons
The number of photons to be skipped during photon mapping.
Gathering Scale Text Box
The gathering radius of the photons.
Caustics Checkbox and Pull-down Menu
This effect creates light patterns such as the ones you would see on the bottom of a swimming pool.
Point Light Specular Direction Map Checbox
Speeds up caustics photon map calculations for mirrored or transparent objects in a scene with point lights.
Radiosity Settings
Always Solve Before Rendering Checkbox
This checkbox sets whether or not the Radiosity is recalculated each time a new rendering starts.
When this checkbox is on, even if a result already exists, the Radiosity will be calculated when the rendering starts, and the rendering will be based on these results. Any existing Radiosity data will be deleted.
When this checkbox is off and rendering starts, the rendering is performed using the existing Radiosity data, if any, and if no Radiosity data exists, an alert message is displayed asking you to execute the Radiosity calculation.
Energy Pull-down Menu
Use to specify the area to which the result of the Radiosity calculation is applied when the rendering is performed.
Total Energy
When Total energy is selected, all results of the Radiosity calculation are used for the rendering. You can display shadows from direct light without having to use the shadows of Ray tracing or Shadow map, but some attributes of Texture Mapping cannot be displayed properly in this case.
Indirect Energy
When Indirect energy is selected, only the indirect light data is extracted from the result of the Radiosity calculation, to be used for the rendering. To display shadows from direct light, you need to use the shadows of Ray tracing or Shadow map.
Reflection Factor Text Box
Used to specify the degree to which the indirect light affects the global illumination. The smaller this value, the faster the calculation and the weaker the effect of the global illumination. The default value is 0.7.
Effects Tab
Fish-Eye Distortion Text Box
The Fish-eye Distortion value is shown in this text box. When a value other than 1 is entered, the result of refraction based on the specified value is used for rendering.
From top to bottom: Fish-eye Distortion ratio of 0.752 (the value 0.752 is equivalent to refraction of 1/1.33 obtained by looking down into water from the air), 1 (normal), and 1.33 (the value 1.33 is equivalent to the refraction obtained by looking into the air from under water). Fish-eye Distortion is effective for Ray Tracing or Path Tracing.
Note: Refer to the “Setting the Camera” chapter for details on Fish-eye Distortion.
Panorama Checkbox
Rendering is performed 360 degrees horizontally, centered on the Eye point, when this checkbox is on. The image may be stretched or squished, depending on the size of the Image window.
Note: Refer to the “Setting the Camera” chapter for more details on the Panorama option.
Effector Number Pull-down Menu
This menu is used to choose the number (1 to 10) of the Effector plug-in.
Effector Type Pull-down Menu
The installed Effectors are listed in this menu, and you can choose one of them for each Effector Number. For details on plug-ins and their use, refer to the electronic guide.
Set Button
When you click this button, the settings dialog box for the Effector plug-in selected in the Effector Type pulldown menu is displayed, provided the plug-in has a settings dialog box.
Note: Refer to the “Shade Reference” for details on Effectors.
Misc. Tab
Number of Threads Pull-down Menu
When Ray Tracing or Path Tracing is selected, the rendering calculation task is divided into multiple tasks according to the number of threads selected in this pull-down menu, and processed by the computer. This number should correspond to the number of CPUs installed on the computer, to achieve the highest performance. During the rendering operation, as many block cursors as specified in the pull-down menu are displayed in different colors in the Image window.
Compatibility Pull-down Menu
If you wish to render a Shade scene created in an older version of Shade, select the appropriate version from the Compatibility pull-down menu. This ensures that the surfaces in the scene are rendered correctly.
Premultiplied Alpha Checkbox
This applies anti-aliasing to the background. When switched off, anti-aliasing is not applied to any channel, except the alpha channel. This checkbox is turned on by default.
Note: Refer to “Merging with an Image” in Chapter 14 for details on the Premultiplied Alpha checkbox.
Transparency Affects Alpha Channel Checkbox
This causes transparency to affect the alpha channel. This checkbox is on by default.
Note: Refer to “Merging with an Image” in Chapter 14 for details on the Transparency Affects Alpha Channel checkbox.
Render Transparency Checkbox
The transparency color will be used for synthesis with the background image when this checkbox is on. Regular rendering will be used when this checkbox is off. This checkbox is off by default.
Note: Refer to “Merging with an Image” in Chapter 14 for details on the Render Transparency checkbox.
Single-Sided Faces Checkbox
When Scan Line rendering is being used, and Flat Shading is selected from the Shading pull-down menu, the backsides of surfaces are not rendered when this checkbox is on. Switching this checkbox off will result in normal rendering. This checkbox is off by default.
Rendered with the Single Face checkbox selected. In this case, the image is rendered normally because the front side of the object is visible.
Rendered with the Single Face checkbox selected when the rear side of the object is visible.
Note: Refer to “Front and Back of Surfaces” in Chapter 3 for details on the side of a surface.
Internal Reflection Checkbox
By clicking this checkbox, reflection is calculated not only for the surface but also for the inside of a transparent object. Using this checkbox will increase the quality of rendered transparent objects, though, it may take longer to render a scene that requires a lot of reflection calculations.
The difference between rendering with and without the Internal Reflection checkbox. The checkbox is on for the left object, and off for the right. Ray Tracing is used for both.
Keep Z Checkbox
When this checkbox is on, Z values for all pixels can be retained after rendering.
A Z value represents the distance from the eye point to the surface of an object, using 8 bits or less. You can access the Z values from the plug-in interface, as well as save them with a TIFF file.
Real Color Checkbox
When this checkbox is on, 32-bit RBG values for each pixel are retained after rendering.
You can access these values only via the plug-in interface.
Ray Cast Level Text Box
The Ray Cast Level ranges from 0 to 100, and is set to 5 by default. Issues involving the Ray Cast Level occur for reflection and transmission of light with the Ray Tracing technique. For instance, in the case of reflection, there may be a case in which reflections are repeated many times, such as for mirrors facing each other. Cases such as this can cause extended rendering time. In Shade, in order to avoid unintentionally long rendering times, the number of reflections is restricted. This restriction is set in the Ray Cast Level text box. No reflection exceeding the Ray Cast Level is calculated, and if either black or the background is set to be reflected, the background will be displayed. In transmission, when the Ray Cast Level is exceeded, and if either black or the background is set to be reflected, the background will be displayed. (The Scan Line technique does not restrict the number of times transmission can take place.) In the initial state, the Ray Cast Level is set to 5, though the value may range from 0 to 100.
Rendered with the Ray Cast Level set to the default value of 5. Here, the reflection rays are cast two times from the black sphere to the red sphere, and three times from the red sphere to the black sphere.
Ray Tracing Quality Text Box
The Ray Tracing Quality ranges from 0 to 100, and is set to 50 by default. You can trade off the quality of anti-aliasing for rendering time by adjusting the level of anti-aliasing sampling when using Ray Tracing. For Path Tracing, you can trade off the qualities of reflection, transparency, soft shadow, and depth of field for rendering time by adjusting the number of rays to be distributed. All of these are set as quality values in Ray Tracing.
With Ray Tracing, the quality of anti-aliasing can be improved. Above: 0, below: 1. The difference in quality of anti-aliasing is apparent in the right edges of the dishes.
Quality in Path Tracing. Above: 0, below: 1. The difference in quality of blur by the depth of field effect can be observed.
Ray Tracing Delta Text Box
The Ray Tracing Delta value is an absolute distance in the view plane. In Shade, when a Ray Tracing ray intersects (reflects or transmits through) a surface, Ray Tracing is resumed from a position very slightly advanced along the ray’s direction from the intersection, in order to avoid repetitive intersection with the surface resulting from errors. This tiny length is called the “Ray Tracing Delta”. The initial value of Ray Tracing Delta is a relative value, and is set around several hundred-thousandths or several millionths of the length of the bounding box of an object (a cube circumscribing the object, with each plane perpendicular to the coordinate axes). In a scene containing a very huge object, when an object within the length of delta of the larger object does not intersect a ray that intersects the larger object, the Ray Tracing Delta value may be inappropriate. In this case, shadow, transmission, and reflection may be incorrect. Most such cases can be corrected by reducing the value of the delta.
Inappropriateness in Ray Tracing Delta values. Small dishes (diameter 46mm ~ 63mm) placed on top of a huge table (64m x 63m x 32m). The default Ray Tracing Delta value is used in the first figure, and the shadow of the dishes is incorrect.
The delta value is changed to 0.01 mm in the second figure to correct the shadow.
Subdividing Surfaces
Objects are approximated by subdivision into straight lines or polygons while rendering is taking place. The accuracy of the subdivision is controlled by special characters added to the beginning of object names, and as defined in the Surface Subdivision pull-down menu in the Rendering Options. Note that adding anchor points to a line object will change how it is subdivided. In cases such as copying a line object at the same location and adding anchor points to one of the objects, the results of subdivision of the two objects may not correspond exactly. In order to have the subdivisions correspond, you need to insure that the anchor points are located at the same places on both line objects by adding the points before copying the original object. How objects are subdivided is as follows:
Line Objects
Line objects are subdivided and approximated by straight line segments.
Extruded open line objects consisting of two control points. The red objects cannot be approximated if the precision of subdivision is low.
Disks
Rendering with the Scan Line technique will approximate disks using regular polygons. Rendering with the Ray Tracing technique will not subdivide disks into polygons, and always displays smooth contours.
Disks are quick-rendered. In order from (1) to (5): No Subdivision character (or “@”), Coarse (or “>”), Regular, Fine (or “<”) and Very Fine (or “<<”).
Spheres
Rendering with the Scan Line technique will approximate spheres using polygon. Rendering with the Ray Tracing technique and with no Shadow Map used will not subdivide spheres into polygons, and always displays smooth shapes.
Subdividing spheres.
Revolved Objects
Paths of revolution are approximated using regular polygons.
Subdividing revolved objects.
Curved Surfaces
Curved surfaces are subdivided and approximated using quadrilaterals or triangles. When the program determines that the surface ratio of quadrilaterals is low, then a curved surface will be subdivided into triangles. Curved surfaces that are surrounded by 4 anchor points are subdivided into quadrilaterals or triangles based on the specified precision.
Subdividing curved surfaces.
Rounding Edges of Polygon Meshes
Although the roundness of edges depends on the value specified by the Roundness slider in the Polygon Mesh dialog box, you can set the accuracy of re-subdivision when rounding of edges is taking place.
Roundness of 0.1
Roundness of 0.5
Roundness of 1
Number of Subdivisions in the Surface Subdivision Pull-down Menu
The following table lists the number of subdivisions done for various objects set to each level of fineness.
Object Names
Special characters added to object names can be repeated. For instance, when the subdivision is specified as Coarse in the Surface Subdivision pull-down menu, prefixing the object name with “<<” will subdivide two steps finer than Coarse. The @ character always takes precedence over other special characters, so that no subdivision will take place.
@ No subdivision
< Subdivide one step finer than indicated in the Surface Subdivision pull-down menu.
> Subdivide one step coarser than indicated in the Surface Subdivision pull-down menu.
Reducing Rendering Time
The most effective way to reduce rendering time is to use a high-speed computer; in other words, a computer that can process floating-point operations at high speed. In general, this means the newest, most expensive computer possible, using the highest speed microprocessor available. The machine should also be equipped with adequate memory. The operating system will start using a function called virtual memory when the actual memory becomes scarce. This function substitutes high-speed memory with space on the hard disk, which is incredibly slow when compared with the processing speed of the microprocessor. Rendering with virtual memory is completely useless. We strongly recommend that you add more memory if you find that virtual memory is used often for your renderings. Also note that graphic cards do not affect the rendering speed.
How to Reduce Rendering Time
We will summarize some of the methods that can be used to reduce the rendering time by manipulating the software itself. Of course, of image quality must be traded off for reduced rendering time.
Lighten the Operational Load
•Use default settings where possible.
•Change from Path Tracing to Ray Tracing, or from Ray Tracing to Scan Line; Path Tracing requires at least nine times as long as Ray Tracing.
•Avoid using reflection, transparency, refraction, roughness, and irregularities in textures as surface attributes, where possible.
•Avoid using too many lights—particularly area lights, point lights and Spot Lights; set the shadows projected by lights (other than the main light) to 0. Setting no shadows can be very effective.
•Avoid rendering the background--instead, use techniques such as Merge and Backdrop.
•Avoid using anti-aliasing, especially when rendering animations.
Lighten the Memory Load
•Lower the accuracy of surface subdivisions: one lower level of surface subdivision accuracy means reducing the memory requirement by a factor of four. For instance, Very Fine requires about 64 times as much memory as Coarse, and 64 times as much memory is required for each object as well. A frequently used method is to lower the accuracy for all objects, and add “<” characters to the beginning of names of objects which contain curves, to render them more accurately.
•Avoid transforming spheres and revolved objects into curved surfaces as much as possible. This technique is not very effective for Scan Line rendering, but is substantially effective when using many spheres.
•Avoid creating too many unnecessary parts.
•Avoid using needlessly large images in image mapping. If there are multiple objects using the same image, include them in a part, and apply the image mapping to the part. If they cannot be included within the same part, use the master surface function.
•Reduce the size of rendered images.
•Close all other running programs.
ShadeGrid Rendering Server
ShadeGrid allows you to improve rendering speed by using more than one computer to render an image or animation. In order to do this, you need the Shade 10 program (client), ShadeGrid 9 (server), and at least two computers on a TCP/IP network.
The server platform on which Shade 10 operates is not dependent on the client platform. You can simultaneously use multiple server machines, and all of the hardware resources can be fully utilized even in a mixed environment of Macintosh and Windows machines, in order to realize faster rendering. However, the speed of the rendering calculation when using a ShadeGrid may vary significantly in accordance with various factors, such as the speed of the server machine, status of the network, and the scene being rendered.
Using ShadeGrid
Launch ShadeGrid 10 (the server machine) prior to performing any operations. Next launch Shade 10 (on client machine).
Select Rendering > ShadeGrid Manager. Check the “Use ShadeGrid Servers” option. To automatically check for systems running ShadeGrid on your local network, click the “Update” button. To manually enter an IP address of a system running ShadeGrid, click the “Add Server...” button and enter the IP address of the server machine (on which ShadeGrid 10 is running) in the “Input IP Address” dialog. For instance, if the IP address of the server machine is “192.168.0.141” enter that address (without the quotation marks). The IP address is displayed in the IP Address field of the ShadeGrid 10 window.
If you are using more than one server machine, use the return key to start a new line (Ctrl-Enter on Windows) and enter another address. The client program will still run if the Rendering Server program was not launched on the server machine with the IP address entered. The ShadeGrid 9 will not launch itself so it must be launched on the server machine for it to be used by the client.
Turn on the Use ShadeGrid Server checkbox in the Rendering Settings dialog under the “ShadeGrid” tab and press the Render button to start rendering.
The basic operation of the ShadeGrid server is the same for both Macintosh and Windows versions. A “Waiting...” message appears on the ShadeGrid before rendering starts. Once the rendering procedure starts, the ShadeGrid receives data, and a “receiving data...” message appears; then the message “preparing...” appears, indicating that the server has received all its data. When the calculation starts, a “computing...” message appears on the ShadeGrid 10 Rendering Server. While the calculation is in progress, colored blocks appear in the Image window on the client machine, in addition to the normal grey blocks. Finally, when rendering is completed, the “waiting...” message reappears on the ShadeGrid server.
The rendering calculation will continue on the client machines and other ShadeGrid servers even if one ShadeGrid server is terminated. ShadeGrid can also be added to the calculation process while it is being processed. However, in this case, rendering needs to be started with the appropriate IP addresses of all the Rendering Servers entered in the “ShadeGrid” tab of the Preferences dialog box.
Appending a “#” (pound) sign to the beginning of an IP address will disable the ShadeGrid Server with that IP address.
Notes on Using ShadeGrid
Only the Ray Tracing and Path Tracing techniques can use ShadeGrid Servers. The ShadeGrid Servers are not used when rendering with the Scan Line technique (i.e. the rendering is performed completely on the client machine).
ShadeGrid Servers are only used for rendering calculations.
Because the ShadeGrid Server functions use a TCP/IP network and IP addresses, the number of server machines that can be used depends on the network environment. For instance, normally in a Class C network, a total of 256 IP addresses can be used. Normally two addresses are used for broadcasting and one is used by the client machine. Consequently, you can use up to 253 addresses for server machines.
Batch Rendering
Bath rendering allows you to queue multiple Shade scenes for rendering. By adding several scene files to the batch rendering queue, you can start rendering and then walk away from the computer, and all the scenes in the queue will be automatically rendered in order.
To open the Batch Rendering window, select Rendering > Batch Rendering.
Adding Active Scenes to the Queue
1. Adjust the rendering settings for each individual scene. Leave each scene file open (active in Shade).
2. Switch to the scene you wish to add to the batch rendering queue, and select Add Current Scene from the Add Scene pull-down menu.
3. Repeat step 2 for the other scenes you wish to batch render.
4. An active checkbox is shown next to the scenes that will be included in the batch render. By default, all the scenes in the queue will be included. If you wish to remove a scene from the batch render without removing it entirely from the queue, deselect the checkbox next to that scene.
5. Click the Start button to begin the batch render.
Adding Other Scenes to the Queue
Scenes do not need to be currently open (active) to be batch rendered.
1. Select Add File from the Add Scene pulldown menu. Alternatively, if you wish to add every Shade scene in a folder, select Add Files From Folder.
2. Select the file you wish to add to the batch rendering queue and click OK.
3. Click the Start button to begin the batch render. |
