How do you add thickness, ensure watertightness for geometries before

[magneto]

Hi,

Is using PolyExtrude the defacto way to add thickness to surfaces and making sure there are no holes, etc?

I find PolyExtrude a little hard to use if the surface is curved, so you get squashed faces at one end of the geometry that you need to clean up, but it's not always possible to just flatten them. You also need to relax them, etc.

What's the best way to do these so that the geometry is not paper thin like a deformed grid or that it's not watertight?

Thanks

[0rr]

can you make your question more precise? Is your mesh closed or does it have boundarys?

However relevenat paper: http://www-bcf.usc.edu/~yongchen/Research/RPJThickening.pdf

[magneto]

I mean if you have an open surface like this:

I use PolyExtrude but often times the faces on the extruded end gets pinched and squashed so it creates artifacts.

[Skybar]

Can't you just extrude straight down? Instead of each face extruding in its own direction.

[kgoossens]

Id like the answer to this too, I think what you are asking for is a 3 dimensional implementation of a straight skeleton.

Something like this?

http://www.graphics.rwth-aachen.de/media/papers/EG08_Pavic_offset_041.pdf

[magneto]

Thanks all.

@Skybar: I guess so, if I could remember that feature So I imagine this is case by case basis depending on the geometry.

Can either of those papers be implemented in Houdini using the standard tools without using the HDK? I will take a look at it for curiosity, but probably be over my head in some parts.

[kgoossens]

You might want to think of something like transforming the deformation in uv space and clipping over there. The example is not working fully but might be able to help.

SelfClipping.hipnc

[0rr]

if you are looking for a quick and dirty solution you may use volumes

flathenthick.hip

Edited December 11, 2013 by 0rr

[magneto]

Thanks 0rr, that's a pretty good approach. How do you judge the success of a volume though? When I display the vdbfrompolygons1 node, I only see individual "pixels" in the viewport which makes me think the volume wasn't constructed correctly. Apparently this is not the case, but I was relying on what I see in the viewport.