Assign Vertex Colors
The Assign Vertex Colors utility assigns vertex colors based on the material assigned to the object and the lighting in the
scene. The utility applies a VertexPaint modifier to the object when Assign To Selected is clicked. Once the VertexPaint modifier has been applied to the object, go to the
Modify panel or click Edit to access the VertexPaint tools.
To render vertex colors, you must apply a material that has a Vertex Color map
in its diffuse component. To view vertex colors in viewports, right-click the object, choose Object Properties
from the quad menu, and then turn on Vertex Channel Display in the Display Properties group and make sure the drop-down option
is set to Vertex Color.
The Assign Vertex Colors utility supports light inclusion or exclusion when using the Scene Lights option.
All of the commands found within the Assign Vertex Color utility are also available from the Modify panel when a VertexPaint
modifier has been applied to an object.
Vertex Colors and Radiosity
The Vertex Colors utility supports radiosity. If you use radiosity with assigned vertex colors, be sure to turn on the option Re-Use Direct Illumination From Radiosity
Solution. This option is in the Rendering Parameters rollout. See Radiosity Controls. When this option is on, the renderer simply displays the vertex colors assigned by the radiosity solution: strictly speaking,
it is not rendering at all.
The additional option Render Direct Illumination, also on the Rendering Parameters rollout, causes direct lighting not to
be saved in the corresponding mesh. This corresponds to the options Radiosity, Render Direct Illumination, in which case Assign
Vertex Colors gets indirect illumination from the radiosity mesh but renders direct illumination separately; or Radiosity,
Indirect Illumination Only, in which case Assign Vertex Colors doesn't apply direct illumination to vertices at all.
To use the Assign Vertex Colors utility:
- Assign materials to the objects you want to affect. These can be mapped or unmapped materials.
- Light the objects.
- Select the objects you want to affect.
- Open the Object Properties dialog for each object, click to turn off the By Layer button, turn on Vertex Channel Display, and click OK.
- Expand the Display Properties rollout in the Display panel and turn on Vertex Colors.
- Access the Assign Vertex Colors utility.
- Choose one of the Light Model options.
- Choose one of the Color Assignment choices.
- Click Assign to Selected.
VertexPaint modifiers are applied to the selected objects, and the vertex colors for the objects are taken from their materials
and from the lighting in the scene, depending on the options you choose under Light Model.
Changing the material or the lighting in the scene won’t change the vertex colors. To do this, click the Update All button.
NoteThe new vertex colors are stored in the Vertex Paint modifier. If you want to access them, go to the Modify panel and access
the parameters in the rollouts there. You can also use the tools found in the Vertex Paint floating dialog to create layers,
paint, blur or adjust color. The Vertex Paint floater launches when you go to the Modify panel and the object is selected.
Example: To use the Assign Vertex Colors utility on a specific object:
- Create a sphere with 24 segments.
- Apply a mapped material to the sphere, and turn on Show Map In Viewports.
The mapped sphere is displayed in the viewport.
- Apply a mapped material to the sphere.
NoteChoose a simple, well-defined map with large, easily-distinguished areas.
- Open the Object Properties dialog for the sphere, and if the button on the right side of the Display Properties group reads
“By Layer,” click it so it says “By Object.” Also in the Display Properties group, turn on Vertex Channel Display and click OK.
- The sphere turns white because you're now displaying its vertex colors, and they're all white as a default.
- With the sphere selected, open the Assign Vertex Colors utility.
- Choose Shaded and turn on Use Maps.
- Turn on Mapping.
- Click Assign To Selected.
A blurred version of the mapping appears on the sphere. The vertices are now colored based on the material and the lighting
in the scene. The mapping is blurred because the resolution of the mesh at 24 segments is much lower than the pixel resolution
of the map.
- Go to the Modify panel and note the VertexPaint modifier.
- Move down in the stack to the creation parameters, click Yes at the warning prompt, and increase the Segments to 70.
The new vertices shift the already assigned vertices.
- Return to the VertexPaint level of the stack, and click Assign in the Assign Vertex Colors rollout. Had we returned to the
Utilities panel, we would have added another Vertex Paint modifier to the stack; clicking Assign in the VertexPaint Modifier
only updates that modifier.
TipVertex colors will only show up in a rendered scene if you assign the Vertex Color map to the diffuse channel. However, if
you do this, you can't properly update your vertex colors with the Assign Vertex Colors utility. The solution is to assign
a Blend material to your object. Assign the straight diffuse bitmap to Material 1, and the Vertex Color map to Material 2
of the Blend. Switch to 100 percent of Material 2 when rendering, and 100 percent of Material 1 when updating the vertex colors.
Here you'll find tools to choose which channel type the vertex color utility will assign. If you choose map channel, you can
also specify the map channel ID number.
- Choose this to assign a vertex color layer.
- Choose this to assign a vertex lighting layer.
- Choose this to assign a vertex transparency layer.
- Choose this to assign a specifically numbered map channel.
- Map channel spinner
Use this to define the channel number. Available only when Map Channel is chosen.
If a channel has a name defined, it will appear here. Channels can be named using the Channel Info Utility.
NoteAlthough the Color, Illum, and Alpha channels have specific names, in fact 3ds Max does not enforce what kind of data is saved in them, and any of the three channels can contain four-channel (RGBA) vertex
Light Model group
Provides options that let you specify how the surface of the object appears to be illuminated.
Color Assignment group
Lets you specify how colors are interpolated across surfaces.
- (The default.) Colors are interpolated between the center of each face.
Color By Face samples fewer points, so it is the quicker method. On the other hand, results are less accurate.
- Colors are interpolated between vertices.
For each face, this method uses three points instead of one, so it is slower but usually more accurate. An exception can occur
when an object's shadow falls between two vertices: In such a case, the object should occlude lighting, but because only vertices
are taken into account, the shadow is not calculated and a “light leak” occurs.
Rendering Options group
The options in this group let you choose whether to include shadows, texture maps, or a radiosity solution in vertex colors.
You can save a radiosity solution in vertex colors, but not Light Tracer
illumination, which is not stored in the scene's geometry.
When on, shadows are used when the vertices are shaded. Default=off.
TipYou can soften the shadow edge by using the VertexPaint modifier's Paint or Blur tools.
When on, texture maps are used when the vertices are shaded. Default=off.
The radio buttons specify how to use radiosity data.
- (The default.) Do not use the radiosity solution when assigning vertex colors.
This option is the only one available unless a radiosity solution
is present in the scene.
- Includes radiosity in the vertex color assignments, and uses the direct illumination from the solution.
This is comparable to the choice Re-Use Direct Illumination From Radiosity Solution on the Rendering Parameters rollout.
This choice disables the Shadows toggle, because shadows don't need to be recomputed.
- Reminder field
Displays a message that says whether regathering is enabled or disabled. Regathering provides the most accurate radiosity
results, but it can add considerable time to radiosity calculations.
- Radiosity Setup
Click to display the Advanced Lighting panel of the Render Setup dialog, where you can set up and generate a radiosity solution.
If the mental ray renderer is the active renderer, this button is not available.
- Assign to Selected
Assigns vertex colors to the selected objects based on the assigned material, and the choices specified in the preceding group
boxes. Assign to Selected creates a VertexPaint modifier and adds it to the stack of the selected objects.
Click to display the VertexPaint Paintbox, the floating dialog that holds the vertex painting tools.
This button is unavailable if you haven't yet clicked Assign To Selected.