SubD examples and models

thomthom

Hi - to get any first experiences I did a little testing, mainly based on Cottys SubD_04 model above. I was interested on how an existing texture behaves to the SubD process - it's amazing how confidently and fast that works ...

Thanks for sharing that model - it's a nice study of geometry and texture.
At the moment SUbD use simple linear interpolation for the textures. However, I am working with integrating OpenSubdiv into a future release. That will give more options for textures;

Source: http://graphics.pixar.com/library/Geri/paper.pdf

pilou

@Thomthom

In fact all works fine!
It was half my fault! I was too confident of the first reading text!

cotty

pilou

Tron!

pilou

Glitch ?

SUbD finds internal faces and can't be apply! (Who don't exist)
(Artisan subdivides

subd_glitch_v6.skp

thomthom

SUbD Catmull-Clark algorithm require the mesh to be a manifold or a surface without any forks. That model you have there have an edge with four faces connected - the algorithm cannot handle that. In another modelling package where the entities didn't merge you'd get away with it as you could have overlapping edges. But since SU merges entities at all times these types of scenarios becomes a challenge.

OpenSubdiv 3 supports internal faces - maybe it would be able to cope with this as well - I'm not sure. But that's still down the line in the road map.

Box

It would be handy if either SubD or Solid inspector could highlight these annoying joints. They can be a real headache to find manually sometimes.

thomthom

Solid Inspector used to complain about these - but because they where considered false positives in many cases it was changed to ignore them.

I do have ideas for an analytical tool for QFT that will visualize quads from triangles and ngons. Maybe it can lightlight forks as well...

By the way, I tried the model on an experimental build I have where I try to wire up OpenSubdiv and it seemed to be able to cope with it:

OpenSubdiv experimental version

pilou

THx for the explanation and the effort!

panixia

@thomthom said:

I do have ideas for an analytical tool for QFT that will visualize quads from triangles and ngons.

please please auto-detect sausages ad donuts

somewere i should have a "wishlist" i wrote with some examples included too..

Box

Another quick late night doodle just for fun and to help wrap my head around quads.
It's very quick and simple but everything is so easy to manipulate with the combination of QFT, VT and SubD.

SubD Plane Proxy.skp

olishea

nice cotty loving this thread....I'll get involved soon

cotty

@Box: nice plane!
@ olishea: be careful, it's contagious

pilou

Maybe you can also use the very cool Free ManifoldLab (Wings3D inside) for some cool things!

cone_v6.zip

trig.zip

cotty

Find the difference

SCF_Cotty_subd25.skp

driven

got it, two are blue and two are red...

panixia

not sure what you guys are trying to achieve with this kind of experiments?
what's the point with all those triangles?
is just for the sake of testing the algorithm itself or is such topology intended for something?
maybe 3dprinting

here is a children slide done with good old quads

slide 1.JPG
slide 2.JPG

children_slide_purged.skp

ntxdave

Going to show my ignorance

How do you go about drawing things like this with quads? Is there some place I can go to learn the process or do you just draw everything with straight lines?

panixia

dave i made a pretty extensive tutorial a few days ago..didn't you spot it?

ntxdave

@panixia said:

dave i made a pretty extensive tutorial a few days ago..didn't you spot it?
j

Oops...I think I have it book marked on a different computer ( if that is the one about the piece of furniture). My apology. I promise I will watch it. L have been going thru some Blender tuts. I want to learn how to draw things better.