MayaMan Help Contents

# MayaMan Subdiv Models

If your renderer supports Subdivision Surface primitives, then you can have MayaMan export these using your existing polygon mesh geometry. The MayaMan Subdiv tools can be found under the Main MayaMan menu.

### Render Selected Objects as Subdivs

Choosing this menu option will cause all the selected polygon mesh objects to be rendered as Subdiv surfaces. By default they are rendered completely smooth with no sharpness creasing. This menu option is a shortcut for opening the model attributes dialog and setting the 'Render as Subdiv' attribute.

### Subdiv Edge Tool

This tool enables you to set the sharpness value of edges in your model. To use this tool, select the edges you wish to sharpen, then select this tool. You will then be able to click in the viewport and drag up and down to modify the sharpness values.

### Subdiv Vertex Tool

This tool enables you to set the sharpness value of vertices in your model. To use this tool, select the points you wish to sharpen, then select this tool. You will then be able to click in the viewport and drag up and down to modify their sharpness values.

### Create Stitch Set For Selected Objects

Select objects that have edges which should be stitched together and select this option. A set will be created that contains sets of pairs of sets of edges. The set just below the top level contains the stitch identifier and the tolerance value used to create the set, neither can be changed after the fact. Only objects that have 'interpolate boundary' on will be stitched and will be emitted as a single chunk (use facevarying if required). To make the selection process easier, any transform node in the selection set will be recursed and scanned for mesh nodes.

In order to improve the continuity between surfaces, the polygons at from one model that touch the seam with a second model will be automatically added to the second model as holes (and vice versa). This largely overcomes the limitations related to not supporting stitching between meshes that have interpolate boundary turned off.... that is to say, to use stitching with interpolate boundary off you'd have to model a ring of overlapping polygons around the edge of each model, and then have to keep them in synch. The new method is simpler in that mayaman automatically puts these extra polygons on as holes which makes them as invisible as the ones that would have been erased by the lack of boundary interpolation but is more controlled in that it only has to be applied at the edges that have seams. All this happens automatically, if you want to disable this behaviour for a particular seam then turn off the 'autocontinuity' attribute on the seam set.

Note, the name of the set must contain the string "MayaManSubdivStitchSet".

## Diagnostics

The stitching code logs several messages, most of which are self explanatory. One message to pay attention to is the report about how many seams are created. Provided that the world space bounding boxes of the objects under consideration have some overlap a line will be created that states how many seams were created.

If 0 seams are created this can mean one of two things, either the objects truly do no overlap, in which case the message can be ignored, or it means that no common edges within the requested tolerance were found.

If 1 seam is created then probably everything went as you expected.

If more than one seam is created between two objects it probably means that there are variations in the objects that have caused the chains to be broken. In this case a lines is printed just prior to the line that mentions how many seams were created that gives the distance between the points that broke the chain... this can then be used as a tolerance value on a subsequent stitch attempt (delete the existing seam sets first).

It may be useful to start with a very large tolerance and then dial it down, prman error messages regarding edges being used in more than one stitch are an indication that the tolerance is too large..

## Archiving/DisplacementBaking and Stitching

If you want to combine archiving (or displacement baking) and stitching you must stitch first, then archive/bake. The resulting archives will have stitch seams burnt in that will correspond to the seam data that remains in the scene. Once this process has begun you should not remodel the non-archived chunks of geo involved in the stitch, if remodelling is required then go back to a fully non-archived scene, remodel, restitch then rearchive/rebake.

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