Noob question on smoothing / adding divisions

[Anonymous]

I have a triangular mesh (closed surface) that I am importing.  Each vertex represents a point ON the surface of the object I am modeling.  I would like to increase the number of facets in a way that interpolates the data in a smooth spline-like fashion.

If I "smooth" the mesh, then I get a new surface that is inside the original surface where it is convex, and outside the original surface where it is concave.  If I use "add divisions", it keeps the original flat facets, while adding more polygons inside those flat facets.  I would like to be able to smooth the surface in such a way that all of the original vertices remain in their original locations, while increasing the number of faces - such that added vertices would be placed on some smoothly curving surface that goes THROUGH all of the original vertices. 

Is there a way to do this in Maya?

I hope my description was clear.  A simple example would be a cube.  When you smooth it, you get a sphere that is smaller than the cube.  I would like to get a sphere that goes through the original cube vertices.  In that simple example, you could just smooth it, then scale the result, but that would not work properly for a more complicated surface that has both convex and concave regions.

Any help on how to achieve this much appreciated.  Thanks.

[Anonymous]

I think I get what you're saying. You want to add density to the mesh but you don't want it to "smooth" itself, or change it's shape in any way?

If you harden all the edges (select all the edges, Normals>Harden Edge, or in 2016: Mesh Display>Harden Edge) and then in the Smooth options menu, you can set the operation to preserve hard edges (if you're using 2016, you need to turn on the Maya legacy settings under subdivision type). Smooth the mesh and the shape should be preserved and you will get more density. Smooth whatever normals you need to and you're good to go.

[Anonymous]

Unfortunately, that does not do what I want.  What you suggest seems to do exactly the same thing as Edit Mesh -> Add Divisions.  It keeps the original vertices and edges in place, and increases the resolution of the mesh, but it keeps the faces flat, just with more subdivisions instead of doing what I want, which is to interpolate a smooth surface through the original points.  Thus, a flat (by definition) face at a convex part of the mesh should have the added vertices bulge out a little from that face.  The idea of keeping an edge fixed is actually counter to what I want to do.  What I want to do is to increase the resolution of my theoritically smooth curved surface, which should add curvature to straight edges.

Perhaps the problem is that modeling in MAYA, one is operating on a control surface that defines the modeled surface.  I wish to start with points ON the modeled surface and use those as my control surface.  Perhaps this is impossible in MAYA.

[Anonymous]

Hold the phone Jack!  If I set the smooth controls to linear by setting "Add divisions" to "Linearly", then set "Push strength" to 1.0, I seem to get exactly what I want - at least for the specific case of a very simple convex object.

I will try a more complex object and see exactly how Push strength and roundness affect the result.

[Anonymous]

Sadly, while setting the push strength to 1 does seem to preserver the original points on the mesh, the roundness control seems to be a bit of a hack - it seems to bulge the faces out (or in) by some proportion when subdividing, but it's not clear exactly what it's doing.  Starting from a mostly smooth surface, it looks most reasonable with roundness set to 1, but a little more info on how those parameters work would be helpful.

-JJ

[Anonymous]

Could you upload a picture of the mesh and draw over top of it the effect that you are trying to achieve? I think I need a visual. You're not trying to bevel the sharp corners, are you?

[Anonymous]

How to do that in Maya 2018/19

Now have two option- Maya Catmull-Clark and Opensubdiv Catmull-Clark

How to turn on the Maya legacy settings ? Thanks