Retopo in Rhino + basic questions

Rhino Rhino for Windows
1

I am a 3D artist and have been for about 8 years.

I mainly model in MAX and Maya, light and render in both but more so in Arnold Maya.

I only really poly modeled and recently tried Rhino and I loved how easy it is to pick up and how well Booleans work. it is like Shape first, finished product second where as poly modeling it is Topology first, modeling second, fixing warping mesh third, etc :stuck_out_tongue:

Anyway, I am getting my hands on laser scan data and I am wondering if it is best to literally lay surfaces over it and fillet edges where they need to be filleted and Boolean where i need to Boolean etc. Pretty much model a car in Rhino with the 3D scan as a 3D guide or is there an easier way.

Some of the burning questions I have are:
I have designed a car in Maya,
A) Can I convert my polymesh to a more simplified nurbs surface? By that I mean where I may have 5 edge loops going through a simple hump, Rhino gives me the least number of nurbs edges that can make that hump.

If you have an edge that is filleted at say 3CM and it is going through a section you booleaned - imagine a crease on a side of a car going through the wheel arches -
B) Can you move this edge and the fillet will move up or down and get ā€œuntrimmedā€?
C) is there some for of history in case you want to adjust such edges?
D) If you did a Boolean operation, can you move the ā€œoperandsā€ and get a near-live update?

Cheers

2

Check out this wiki page on the subject of reverse engineering or the act of creating a NURBS model from a mesh.
http://wiki.mcneel.com/rhino/reverseengineering

I do this manually using Vertex Osnaps on the imported mesh while drawing the curves for the surfaces. Then Loft, Sweep or NetworkSrf with History Recorded and you can edit the curves to update the resulting surface. Thereā€™s no history or what you might think of as a modifier stack for fillets or Booleans currentlyā€¦ so do those bits last. Your poly modeling experience will be helpful here, think of the NURBS surfaces you make in the same way youā€™d try to model with all quads. Four sided untrimmed surfaces will provide the most flexibility.

With all that said, there are some methods of auto converting a low level of detail all quad mesh to a NURBS polysrf using the Tsplines plugin for Rhino. The last time I looked it didnā€™t do well with lots of polys or tris but you may be able to find a trial version to give it a shot. The manual method still gives the most control over the surface flow in my opinionā€¦ it just takes time.