reverse proxies and shrinkwrapping

[blindsaypatten]

I'm wondering if the idea of a "reverse proxy" has ever been brought up or discussed. By reverse proxy I mean a mesh that has a desired shape being used to shape the basemesh, similar to the way that changes in the base mesh change the shape of proxy objects. It would be nice if I could produce the shape that I want with some arbitrary mesh and then have the basemesh conform to that shape. I'm primarily thinking of use for local features rather than the entire body. For example, if I model the jaw line that I want using a mesh whose topology matches the shape of the jaw, I could then position that mesh where I want the jaw to be and then have the base mesh surface conform to the surface of my mesh. I've never used shrinkwrapping in Blender but I think that it works something like this, and perhaps the thing for me to do is to perform this shrinkwrapping in Blender and then generate a target from the shrunkwrap base mesh.

Another use case would be using a 3D scan or existing mesh of a body part or face to shape the basemash. I tried using Sculpture Mode in Blender on the basemesh and was successful with some things, but the basemesh topology made some things difficult. If I could sculpt on a different mesh, or use dynamic topology, it would be easier to achieve the shape I want and then transfer it, as best as possible, to the basemesh to make a target with.

Has anyone done anything along these lines?

[brkurt]

I'm wondering if the idea of a "reverse proxy" has ever been brought up or discussed. By reverse proxy I mean a mesh that has a desired shape being used to shape the basemesh, similar to the way that changes in the base mesh change the shape of proxy objects. It would be nice if I could produce the shape that I want with some arbitrary mesh and then have the basemesh conform to that shape. I'm primarily thinking of use for local features rather than the entire body. For example, if I model the jaw line that I want using a mesh whose topology matches the shape of the jaw, I could then position that mesh where I want the jaw to be and then have the base mesh surface conform to the surface of my mesh. I've never used shrinkwrapping in Blender but I think that it works something like this, and perhaps the thing for me to do is to perform this shrinkwrapping in Blender and then generate a target from the shrunkwrap base mesh.

Another use case would be using a 3D scan or existing mesh of a body part or face to shape the basemash. I tried using Sculpture Mode in Blender on the basemesh and was successful with some things, but the basemesh topology made some things difficult. If I could sculpt on a different mesh, or use dynamic topology, it would be easier to achieve the shape I want and then transfer it, as best as possible, to the basemesh to make a target with.

Has anyone done anything along these lines?

There is some very interesting history on this topic. We had (I believe in 2009) a medical researcher who made the same request. He want a (very) high-count polygon mesh so that when someone wiggled during an MRI scan, he could use the mesh template to stabilize the data.

Be that as it may, be careful trying to solve body-shape problems with the Shrinkwrap modifier. I've mentioned this several times in the forum: the Shrinkwrap will attempt to re-mold your desired mesh to a rigid XYZ grid, which of course is the exact opposite of what you want in an organic shape. It's a new version of the classic Greek problem of 'squaring the circle'.

[blindsaypatten]

As a test, I created a nurbs surface in blender and converted it to a mesh, which I then embedded in the basemesh to roughly represent a cheekbone (although it looks more like a tumor). Once I had it where I wanted the cheekbone to be I selected all the vertices under the nurbs mesh and shrankwrap them to the nurbs mesh. I think the result is not too bad. The shrink wrapping result that is, it's a lousy cheekbone but that's wasn't the point. I moved the nurbs mesh away from the face for illustrative purposes, when it was positioned on the cheek the part that protruded was pretty much exactly what the resulting cheekbone looks like.

Now I just have to learn how to model with nurbs, beyond scaling. Also, I have to try this with a mesh from a 3D scan.
I think you could probably produce a decent bicep this way, other muscles too.