Create Bitmap / BitmapSelect                               

In this section you can find information about the Create Bitmap and BitmapSelect tools in PolyBoost

Quick navigation:

Bitmap Select
Cavity Map
Density Map
Dust Map
SubSurface Map
Selection To Bitmap
Texture Wrap

BitmapSelect

Press this button to open the BitmapSelect dialog.

With this tool you can select parts of the model based on a bitmap image. The chosen bitmap is applied based on the models UVW mapping and selects parts of the mesh which corresponds to a defined color. As an example you can select all polygons which have the color white in the chosen bitmap. This way you can have a selection saved which will survive many topology changes, and quickly select hard to reach areas of the model. You can also have many selections stored in the same bitmap, since every color in the bitmap can be defined as a separate selection. It is recommended that you use lossless formats for the bitmap like .tga, .bmp or other, since a format like a compressed .jpg can loose some color information in the compression

This tool works for all subobjectlevels. To determine weather a subobject-element has the "right" color in the bitmap there are these principles:

In vertexmode the vertex must have the defined color in order to be selected.

In edgemode the middle of the edge must have the defined color in order to be selected.

In polygonmode the middle of the polygon must have the defined color in order to be selected.

These principles can be used when painting a bitmap for selection where you want specific subobject-elements selected.

Map1-Map4: These mapslot buttons are used to select which bitmap to use for getting the selection. When you press a button the standard max mapselector comes up. The "C" buttons next to each mapslot are used to clear the corresponding mapslot.

Use mapslot:

Determines which of the mapslots will be used for getting the selection.

Mapchannel:

Determines which mapchannel is used when getting the selection.

Get selection from:

Determines which color in the bitmap will be used for getting the selection. If it is set to "White" and the subobjectlevel is polygon, all polygons which have a corresponding white color in the bitmap based on the UVW layout will be selected. In the colorpicker you can pick the color which will be used to get the selection. There is a slight tolerance for the color so the color does not have to be exact but is allowed to differ slightly.

GO

Gets the selection from the bitmap.

Create Bitmap

These are a set of tools for creating bitmaps based on an objects uvw mapping. The bitmaps display certain surface properties of the object.

These setting apply to all tools in the Create Bitmap section:

W and H: Sets the width and height of the bitmap to generate.
Size: Here you can choose some predefined sizes for the bitmap.
Mapchannel: Determines which mapchannel is used when generating the bitmap.
SeamBleed: This value determines how many pixels are added at uvw borders as "padding". These bleeded pixels will never overwrite the pixels within uvw seams. This value has no effect in SelectionToBitmap.

Cavity Map

This tool will generate a greyscale 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 the pixels. This image can then be used as a cavity or "dirt" map, or as a base for further texture painting.

The ExtraContrast spinner 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 migth be neccessary to add more contrast to get the difference in concavity/convexity to show clearly.

The image displays a Cavity map created from a character head.

Density Map

This tool will generate a greyscale image that displays how dense the surface of an editable poly object is at a given point. The image goes from white to black where white represents the smallest distance between vertices and black represents the biggest distance.

The image displays a Density map created from a character head.

Dust Map

This tool will generate a greyscale image that displays how much the surface is pointing in the world Z direction at a given point. The image goes from white to black where white represents vertices pointing fully in the Z direction and black represents vertices pointing 90 degrees from the Z axis or below.

The image displays a Dust map created from a character head.

SubSurface Map

This tool will generate a greyscale image that displays an estimation of how thick the surface of an editable poly object is at a given point. The image goes from white to black where white represents the thinnest parts and black represents the thickest parts. This map can then be used to simulate more ligthness at thin parts if the material is semi translucent. The generated map in no way accurately represents how light would pass through the surface but can be useful for such purposes.

The Scale spinner value determines how much of the surrounding area at a given point is checked in calculations. For lowres objects this value should not be very high. For highres objects turning this value up can produce better results. 

The image displays a SubSurface map created from a character head.

SelectionToBitmap

A black and white bitmap will be generated based on the current subobject selection and displayed in the frame buffer from where it can be saved. White color a means a selected subobject-element at that location. In vertexmode each vertex will get a white dot. In edgemode each edge will get a dot in the middle of the edge. In polygonmode each polygon will be filled with white color. A bitmap generated with SelectionToBitmap can then be used for selecting subobject-elements with the BitmapSelect tool.


Example of how a bitmap can look when SelectionToBitmap is used. Each dot in the bitmap here represents a selected vertex.

Shortcut: When used as a shortcut the SelectionToMap works as follows:

Normal: A bitmap will be created in the size of 256x256.

Shift: A bitmap will be created in the size of 512x512.

Texture Wrap

This tool will create a texture map from an input texture and wrap it around the selected object in a way that creates no texture seams and at 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. You can as an example create a basic skin texture and wrap that around the whole character model in a seamless way. Another good use is for complex shapes like a tree and all its branches.

Use the "Pick Texture" button to pick the input texture. Select an editable poly object and press "Texture Wrap" to create the texture. You can then save and apply the texture in the diffuse map slot of the objects material to see the result. The Tile spinner detemines how many times the input texture is tiled. With tiling set to 1.0 the input texture itself does not need to be tilable in most cases.


The first image shows the selected input texture. The second one shows the generated texture applied to the model.

Tip: For complex objects you can use the "Flatten Mapping" feature in 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 a good result across texture seams.

Note: For very low resolution models that has a lot of sharp angles between faces this tool might not produce a satisfying result. It works best for organic surfaces that has a bit of curvature.


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