Closing holes in a poly mesh
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- Arjuna Ravikumar
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Newbie Houdini user here! (Apologies if I posted this twice - I can't seem to find my previous post)
I created this geometry through various steps and now I need to close out the holes in it. I'm sure there's an easy way to do this but I can't think of one.
I tried:
1. Extruding the unshared edges and trying to collapse them to a point, but had no luck there.
2. Tried “divide” -> remove shared edges (and then reverse), but I get some blobs that I did not intend. (screenshot attached).
I created this geometry through various steps and now I need to close out the holes in it. I'm sure there's an easy way to do this but I can't think of one.
I tried:
1. Extruding the unshared edges and trying to collapse them to a point, but had no luck there.
2. Tried “divide” -> remove shared edges (and then reverse), but I get some blobs that I did not intend. (screenshot attached).
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- mandrake0
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if it's a test file it would be nice to post the hip file.
there are some SOP nodes to solve the problem:
- fuse
- PolyDoctor
- PolyStitch
- Clean
some doc:
http://www.sidefx.com/docs/houdini13.0/model/repair_polys [sidefx.com]
there are some SOP nodes to solve the problem:
- fuse
- PolyDoctor
- PolyStitch
- Clean
some doc:
http://www.sidefx.com/docs/houdini13.0/model/repair_polys [sidefx.com]
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- Arjuna Ravikumar
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Thanks! Those are some sops I hadn't even considered. I'll start looking into them.
I've attached the hip file which is unfortunately very cluttered at the moment.
There's a branch on the Left which is the one I'm working on.
Ignore the one on the right - it does the job, but also generates unwanted polygons.
I have left comments for the two branches.
Unfortunately I'm going to be out on break for the next 10 days, so I might not check or reply to this thread. Thanks for the information. I'll play with it to see what I get.
Happy holidays!
I've attached the hip file which is unfortunately very cluttered at the moment.
There's a branch on the Left which is the one I'm working on.
Ignore the one on the right - it does the job, but also generates unwanted polygons.
I have left comments for the two branches.
Unfortunately I'm going to be out on break for the next 10 days, so I might not check or reply to this thread. Thanks for the information. I'll play with it to see what I get.
Happy holidays!
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- old_school
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PolyCap SOP fed an unshared edge group built by the Group SOP should normally do the trick.
It will cap all the holes but it will also create a lot of extra faces as your input geometry isn't ideal.
You have lots of knitted triangle regions that the PolyCap will not cap cleanly. It sees a single connected poly loop of 2 or more triangles sharing only one point each. It will bridge all the ploys filling in the concave areas as well.
Just what result are you after btw? It isn't too clear from your scene file.
It will cap all the holes but it will also create a lot of extra faces as your input geometry isn't ideal.
You have lots of knitted triangle regions that the PolyCap will not cap cleanly. It sees a single connected poly loop of 2 or more triangles sharing only one point each. It will bridge all the ploys filling in the concave areas as well.
Just what result are you after btw? It isn't too clear from your scene file.
There's at least one school like the old school!
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- Arjuna Ravikumar
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I'm trying to take any input geometry - convert it to a voxelized geometry (i.e. represented by cubes) like in Minecraft.
Then I'm trying to smooth those hard corners of the cubes to more gentle slopes like you can see in my first image. I.e. every 90 degree edge between two faces will get deleted and replaced by a 45 degree slope.
The corners get a little more complex, but basically follow the same principles.
I'm not sure if that explanation helps at all
Let me know.
Then I'm trying to smooth those hard corners of the cubes to more gentle slopes like you can see in my first image. I.e. every 90 degree edge between two faces will get deleted and replaced by a 45 degree slope.
The corners get a little more complex, but basically follow the same principles.
I'm not sure if that explanation helps at all

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- mandrake0
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- mandrake0
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- Arjuna Ravikumar
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Thanks so much for the examples! They're pretty good, but still aren't achieving the exact look I was going for. It was helpful to learn more about VEX though.
I found this image online:
https://raw.githubusercontent.com/maxogden/ndarray-stl/master/img/mario-makerware.png [raw.githubusercontent.com]
The effect on the right-most model is what I'm going for. Is there a term for that sort of voxel smoothing? Is there an existing algorithm that creates it? I don't know what to google for
I found this image online:
https://raw.githubusercontent.com/maxogden/ndarray-stl/master/img/mario-makerware.png [raw.githubusercontent.com]
The effect on the right-most model is what I'm going for. Is there a term for that sort of voxel smoothing? Is there an existing algorithm that creates it? I don't know what to google for

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- pezetko
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It's using marching cubes algorithm as it is written in comment below the image:
http://voxelbuilder.com/ [voxelbuilder.com]
And there is even direct link to the wikipedia that describes that algorithm. :wink:
http://voxelbuilder.com/ [voxelbuilder.com]
And there is even direct link to the wikipedia that describes that algorithm. :wink:
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- Sergey Filin
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old_school
PolyCap SOP fed an unshared edge group built by the Group SOP should normally do the trick.
It will cap all the holes but it will also create a lot of extra faces as your input geometry isn't ideal.
You have lots of knitted triangle regions that the PolyCap will not cap cleanly. It sees a single connected poly loop of 2 or more triangles sharing only one point each. It will bridge all the ploys filling in the concave areas as well.
Just what result are you after btw? It isn't too clear from your scene file.
You can follow up the polycap node with measure node and blast node to delete the primitives (groups of primitives) from the patch group which are too big.
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