Lyubomir, thanks!
It is already merged into sidefx labs project(https://github.com/sideeffects/SideFXLabs). Thus, not sure if it is the latest version..
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Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
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Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
- 31 posts
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@jason_iversen
Honestly, I have no idea. The weight map should look like a thickness/density map. If you combine that with skeleton curve partitioning(limb partitioning) you might get some localized effect similar to the biharmonic weighting. I don't know..
Honestly, I have no idea. The weight map should look like a thickness/density map. If you combine that with skeleton curve partitioning(limb partitioning) you might get some localized effect similar to the biharmonic weighting. I don't know..
Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
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v7:
- removed several seconds from the post processing phase
- skeleton thinning much faster
- removed some unneeded stuff from the curve refinement phase, also much faster
- the entire process for squab in less than 6 sec - skeleton extraction, thinning and curve refinement
BTW, @lkruel did a great job of integrating a 3d skeleton solution based on this stuff into the game toolset. Luiz, thanks! ..and a thumb up emoji would be nice in the comment section
- removed several seconds from the post processing phase
- skeleton thinning much faster
- removed some unneeded stuff from the curve refinement phase, also much faster
- the entire process for squab in less than 6 sec - skeleton extraction, thinning and curve refinement
BTW, @lkruel did a great job of integrating a 3d skeleton solution based on this stuff into the game toolset. Luiz, thanks! ..and a thumb up emoji would be nice in the comment section
Edited by rpopovici - 2019年8月15日 11:17:56
Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
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@jason_iversen right now I am not in front of it, but I believe @probiner has some skeleton based animation example. I am assuming here that it’s based on Deform SOP..
As for weight capturing, this can be done but it might not be what you want because the skeleton is determined in two steps. First, determine the skeletal surface, then reduce that to a curve skeleton. So, the gradient trace is not exactly a straight curve normal to surface
As for weight capturing, this can be done but it might not be what you want because the skeleton is determined in two steps. First, determine the skeletal surface, then reduce that to a curve skeleton. So, the gradient trace is not exactly a straight curve normal to surface
Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
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More improvements to this project
- found a way to optimize vdbfrompoly
- incresed 2x default voxel size from 0.002 to 0.004
- VDB smooth with curvature flow
- replace Ends SOP with Split SOP
- skeleton thining as post process
- perf improvement up to 5x in most cases
- found a way to optimize vdbfrompoly
- incresed 2x default voxel size from 0.002 to 0.004
- VDB smooth with curvature flow
- replace Ends SOP with Split SOP
- skeleton thining as post process
- perf improvement up to 5x in most cases
Edited by rpopovici - 2019年7月9日 03:24:39
Technical Discussion » Convert multiple attributes to groups
- rpopovici
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I don't understand what you are trying to do here, but you can take a look at these SOPs: Connectivity SOP, Partition SOP, Name SOP, Group Expression SOP, and Group Promote SOP. They all deal with groups form attributes or the opposite..
Technical Discussion » Finding and grouping overlapping Points or Verts
- rpopovici
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In H17.5 you have FuseSOP v2. Turn off “Fuse snapped points” and activate “Snapped points group” option. This will create a group with snapped points. Then you can use a GroupCopy SOP to transfer the newly created group back to the original mesh - before fuse/snapping.
Houdini Indie and Apprentice » How to separate into individual pieces
- rpopovici
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Splitting into pieces by attribute type(Vertex, Point, Edge, Primitive) can be done with: VertexSplit SOP, Facet SOP -> Unique Points, Edge Cusp SOP and PrimitiveSplit SOP. Also you can use Split SOP with groups of primiteves and then use Merge SOP to merge it back.
Technical Discussion » Point Edge Direction
- rpopovici
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Append a Reverse SOP before the PolyFrame.. More here https://www.sidefx.com/forum/topic/18287/ [www.sidefx.com]
Technical Discussion » Filling and closing holes on volumetric capture
- rpopovici
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As for color filling, you can use attribute transfer SOP. It will automatically fill the area which has no correspondence to the original mesh.
Like this:
Like this:
Technical Discussion » Filling and closing holes on volumetric capture
- rpopovici
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Technical Discussion » Filling and closing holes on volumetric capture
- rpopovici
- 31 posts
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Have you tried MeshLab or MeshRoom for this stuff? Both are free.. Also you can try to use the tools from AliceVision integrated with Houdini's game tools.
Big holes are difficult to close. You have to manually take care of them by creating/deleting geometry in this area. You can use VDB to convert a point cloud into a mesh. And you can easily get rid of noise by running VDBSmooth followed by a VDB Dilate.
Here is an example:
Big holes are difficult to close. You have to manually take care of them by creating/deleting geometry in this area. You can use VDB to convert a point cloud into a mesh. And you can easily get rid of noise by running VDBSmooth followed by a VDB Dilate.
Here is an example:
Edited by rpopovici - 2019年5月17日 08:46:21
Technical Discussion » How to create uv along the line vector in Polyexpand2d ?
- rpopovici
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Anyway, in reality you have only a few types of crossings like: X shape, T shape and ring.. If you want quads only, then you can extrude each curve separately which will result in overlaping intersections. Then you can offset intersecting polygons along Y axis a little bit to avoid Z-fighting.
My take on this - quads only, except for crossings.
My take on this - quads only, except for crossings.
Technical Discussion » Normal point outwards of curve?
- rpopovici
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You can try to append a point wrangle node after PolyFrame SOP and compute the cross product like this: v@N = cross(v@tangentu, v@N);
It should give you what you want..
It should give you what you want..
Houdini Indie and Apprentice » How to insert a point on edge
- rpopovici
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Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
- 31 posts
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- for some reason, gradient normalization gives faster advection in flat volumes. Probably in this case gradient's magnitude is smaller before normalization..
- added a stop condition in case the skeleton is computed in less steps than iteration count
- added an auto uv example based on straight skeleton and find shortest path
- added a stop condition in case the skeleton is computed in less steps than iteration count
- added an auto uv example based on straight skeleton and find shortest path
Edited by rpopovici - 2019年5月1日 16:06:14
Technical Discussion » tetrahedralize houdini 17 doesnt create connections inside my mesh?
- rpopovici
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Apparently you have to use Connected Polylines as output in TetrahedralizeSOP if you want to get the polyline connections
Technical Discussion » tetrahedralize houdini 17 doesnt create connections inside my mesh?
- rpopovici
- 31 posts
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You can try Vellum Configure Tetrahedral Softbody SOP configuration and then from the second output you can extract your tetrahedra internal polylines
Technical Discussion » Creating faces from a wireframe.
- rpopovici
- 31 posts
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You can try Tetrahedralize, ConvexHull or VDBFromParticles. Also if you can isolate every three points based on connectivity or distance you can use Add SOP or PolyFill to convert those to a polyggon..
Technical Discussion » Skeleton curve implementation based on VDB medial axis
- rpopovici
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Pedro, I totally agree with you. Straight skeleton is like philosopher's stone for 3D. You can use it for pretty much anything once you have it.
In reality, a 3D straight skeleton is not exactly a curve. It's more like a surface which can be further degraded into a curve. Tubes and pipe like meshes will resolve faster to a curve, but stuff like a flat or concave mesh, will take longer to resolve because you are limited by the voxel size and VDB internal representation of the volume(multiple B-tree center nodes). You can apply more median SDF smothing in order to eliminate surface disturbances but also it will give you a faster resolve towards the end result. If you want to know how a real straight skeleton really looks like, you can run Voronoi Fracture SOP with original mesh points as control points. Unfortunately this is extremly slow for high density meshes and also the result is way to branchy.
1. Paint SOP -> smoothing locally with Smooth SOP will eliminate skeleton small branches and it will give you a cleaner skeleton curve.
2. You can use Refine SOP(Unrefine mode) to straighten curves with lower curvature. You can also manually select points you don't want to refine.
Cheers
Radu
In reality, a 3D straight skeleton is not exactly a curve. It's more like a surface which can be further degraded into a curve. Tubes and pipe like meshes will resolve faster to a curve, but stuff like a flat or concave mesh, will take longer to resolve because you are limited by the voxel size and VDB internal representation of the volume(multiple B-tree center nodes). You can apply more median SDF smothing in order to eliminate surface disturbances but also it will give you a faster resolve towards the end result. If you want to know how a real straight skeleton really looks like, you can run Voronoi Fracture SOP with original mesh points as control points. Unfortunately this is extremly slow for high density meshes and also the result is way to branchy.
1. Paint SOP -> smoothing locally with Smooth SOP will eliminate skeleton small branches and it will give you a cleaner skeleton curve.
2. You can use Refine SOP(Unrefine mode) to straighten curves with lower curvature. You can also manually select points you don't want to refine.
Cheers
Radu
Edited by rpopovici - 2019年4月28日 10:04:21
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