Render Surface Map
This dialog provides a set of tools for creating bitmaps based on an object’s UVW mapping. The bitmaps display certain surface
properties of the object. There’s also a Bitmap Select function for selecting sub-objects based on mapping attributes.
These tools work only with editable poly objects. If you attempt to use one with another type of object, even if it has an
Edit Poly modifier applied, nothing happens.
Also, the object must have a map channel (typically 1) corresponding to the current Map Channel setting on the Render Surface Map dialog. If the object has no map
channel, an error message informs you of this fact. To provide a map channel, apply an Unwrap UVW or UVW Map modifier and then convert the object to an editable poly.
Example: To use Render Surface Map:
This procedure describes how to create a surface map and then use it in a material.
- From the Rendering menu, choose Render Surface Map.
This opens the Render Surface Map dialog.
- Select the editable poly object for which to generate the surface map.
- Set the Map Channel parameter on the Render Surface Map dialog to that of the object.
Make sure the object has a mapping channel and that Map Channel is set to that channel. If you attempt to render a surface
map and encounter a message that says that the map channel does not exist, either set Map Channel to the correct value, or,
if the object has no mapping, create mapping for it. To do so, apply a mapping modifier such as Unwrap UVW
or UVW Map
and then collapse
the modifier stack.
Also, for best results, make sure mapping clusters do not overlap. For example, in the Unwrap UVW modifier, use the Flatten Mapping tool.
- Click one of the top four buttons on the Render Surface Map dialog: Cavity Map , Density Map, Dust Map, or SubSurface Map.
For example, to generate a texture that makes the object look dirty in concave areas, use Cavity Map.
After a brief pause, the generated texture opens in a separate window. The texture type (such as Cavity Map) appears in the
window’s title bar.
- On the output window toolbar, click (Save Image). Specify a name, type (graphics format), and location for the file, and then click Save.
- Use the Material Editor to assign the saved image file as a Diffuse map in a material, and then assign the material to the
object you used to generate the map.
The width and height of the bitmap to generate.
TipWhen generating bitmaps for use in real-time-rendering applications, such as games, both dimensions should be powers of 2,
such as 256 or 512.
Choose a size from the list of presets.
- Map Channel
The map channel to use when generating the bitmap.
- Seam Bleed
Determines how many pixels are added at UVW borders as “padding.” These bled pixels will never overwrite the pixels within
This value has no effect in SelectionToBitmap.
- Cavity Map
Generate a grayscale image that displays how convex or concave the surface of an editable poly object is at a given point.
The more concave the surface is the darker the pixels will be and the more convex the surface is the more white is added to
This image can be used as a cavity or "dirt" map, or as a base for further texture painting.
A Cavity map created from a character head
Determines how much extra contrast is added. In a very high resolution mesh the surface does not change much from polygon
to polygon, so in such cases it might be neccessary to increase the contrast to get the difference in concavity/convexity
to show clearly.
- Density Map
Generates a grayscale image that displays how dense the editable poly mesh is at a given point. White areas represent the
smallest distance between vertices and black represents the greatest distance.
A Density map created from a character head
- Dust Map
Generates a grayscale image that the extent to which each point in the surface faces the world Z direction. White represents
vertices pointing fully in the Z direction and black represents vertices pointing 90 degrees from the Z axis (that is, parallel
to the world XY plane) or below.
A Dust map created from a character head
- SubSurface Map
Generates a grayscale image that displays an estimation of the relative volume of a poly object at a given point. White represents
the thinnest parts and black represents the thickest parts. You can then use this map to simulate greater translucency in
The resulting map does not necessarily represent accurately how light would pass through the surface but can be useful for
SubSurface maps created from a poly mesh, showing different Blur values
The upper two images use flat shading so that only the texture is visible.
The degree of blurring applied to the generated map.
In the preceding illustration, the top rendering has Blur set to 4, while the center one has Blur set to 40. The bottom rendering
shows the poly object without a texture map.
- Occlusion Map
Generates a grayscale bitmap based on the extent to which parts of the object occlude other parts. Does not depend on scene
Generates a black-and-white bitmap based on the current sub-object selection and displays it in a window from which you can
White areas in the output image indicate selected sub-objects at that location. At the vertex level each vertex gets a white
dot. At the edge level each edge gets a dot in the middle of the edge. At the polygon level each polygon is filled with white
You can use a bitmap generated with SelectionToBitmap for selecting sub-objects with the Bitmap Select tool (see following).
SelectionToBitmap used at the Vertex level
You can assign CUI shortcuts
(PolyTools category) for SelectionToBitmap. When assigned as shortcuts, the image is generated as follows:
- Creates a 256x256 bitmap.
- Creates a 512x512 bitmap.
This tool creates a texture map from an input texture and wraps it around the selected object in a way that creates no texture
seams and with a uniform texture scale across the surface. It projects the input texture from all directions and blends the
result based on surface normal. A good use for this tool is to provide a base texture for a model. For example, you can create
a basic skin texture and wrap that around the whole character model in a seamless way. Another use is for complex shapes such
as a tree and all its branches.
To use Texture Wrap, first click Pick Texture to specify a texture file, then select the object to wrap and click Texture
The input texture (left) and the resulting wrapped texture applied to a model (right)
For complex objects, use the Flatten Mapping
feature of the Unwrap UVW modifier to create UVW coordinates for all parts of a mesh. You can then use Texture Wrap to wrap
a texture around that object with good results across texture seams.
NoteThis tool might not produce ideal results with very-low-resolution models that have many sharp angles between faces. It works
best with organic surfaces that have some curvature.
- Pick Texture
Opens a file dialog for specifying an image file to wrap as the texture.
The number of times the texture will be repeated across the object, both horizontally and vertically.
- Texture Wrap
With an editable poly object selected, click to wrap the texture.
Enables you to select parts of the model based on a bitmap image.
- Bitmap Select
Opens the Bitmap Select dialog.
- Bitmap Select Dialog
With Bitmap Select you can select sub-objects in the model based on a bitmap image. Bitmap Select applies the chosen bitmap
for selection purposes based on the model’s UVW mapping (it need not be part of a material applied to the object), and uses
it to select parts of the mesh that correspond to a defined color. For example, you can select all polygons that have the
color white in the chosen bitmap.