Trimmed Nurbs To Clean Polys via Skin or otherwise

[archo_p]

Hello!

Relatively new to houdini modelling.  I have some old experience with nurbs modelling from old Rhino days and have been using poly and boolean to some success, but when i'm making inherently 'nurbsy' forms I find it difficult to get back to clean polygons that have good topology preocedurally.  I think there is a simple solution here I am missing so just hoping for some best practices from the masters!  I have a trimmed nurbs surface that I want to get back to polys by skinning the profiles but with cross sections generated along the surface of the source nurbs surface.  Since its trimmed the UV curves of the nurbs aren't super useful.  My hope is to somehow get projected cross sections, convert and re-sample so they have the same number of points and use those as cross sections in a skin sop that takes the re-sampled trim profiles as U boundaries.  Any help or advice about how to approach would be much appreciated.  I am attaching a simple file with a null representing the shape I am hoping for called "idealShape_for_cleanpolys" and then a part of the network where I am crudely converting the profiles to polys for a skin operation, but obviously this has no U sections so is just a simple skin between the two profiles with no V information between the two profiles.

 

Cheers 
P

trimmedNurbsToCleanPoly.hiplc

[Noobini]

I could be on a completely different planet...but doesn't add a convert after your idealShape work?

[anim]

maybe not the most universal solution, depends on the shape

trimmedNurbsToCleanPoly_mod.hiplc

[konstantin magnus]

Hi Archo,

you can create CAD-like shapes by transferring NURBS surface positions to parameterized polygon meshes through curve ramps.

vector uvw = vertex(0, 'uv', i@vtxnum);
float deform_top = chramp('shape_top', uvw.x);
float deform_btm = chramp('shape_bottom', uvw.x);
uvw.y = fit01(uvw.y, deform_top, deform_btm);
v@P = primuv(1, 'P', 0, uvw);

shape_transfer.hipnc

[archo_p]

Thanks @anim!  This is poly bridge/ray solution is exactly the kind of thing i was looking for, thank you!

@konstantin your example is very intriguing, will need to investigate that further to see what is going on there and how it might be of use.

Thank you for your help, this is great!