Here's a fairly efficient take…
You can do the curve building in Vops but it's probably easier to understand this way. When looking up the closest point on a surface it's much more efficient to work on polygons than nurbs.
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Technical Discussion » Gradient Descent
- tjeeds
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Technical Discussion » Changing background value on a VDB
- tjeeds
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Technical Discussion » Changing background value on a VDB
- tjeeds
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I've got a VDB that stores a function value and I'm trying to manually set the background value to no avail. It doesn't appear to be editable as an intrinsic and I can't seem to find a node that will do what I want. It's currently set to 0 and I need it to be 1.
Any ideas on how to accomplish this?
'Preciate ya!
Any ideas on how to accomplish this?
'Preciate ya!
Houdini Learning Materials » SOP context vs CVEX context ?
- tjeeds
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This is the same divide between the VOP SOP and the AttribVOP/VolumeVOP.
Basically CVEX is more generalized and each container type provides unique bindings that can be used inside.
The VOP SOP has some specialized SOP functions such as Import Attribute and Add Attribute which creates a local variable and allows vector casting (things you cannot currently do in CVEX).
CVEX allows you to create and destroy geometry. Most code is interchangeable between the two but CVEX is really the way forward and there very few reasons to use a VOP SOP/Point Wrangle. The OpInput bindings alone have led me to prefer the AttribVOP.
Basically CVEX is more generalized and each container type provides unique bindings that can be used inside.
The VOP SOP has some specialized SOP functions such as Import Attribute and Add Attribute which creates a local variable and allows vector casting (things you cannot currently do in CVEX).
CVEX allows you to create and destroy geometry. Most code is interchangeable between the two but CVEX is really the way forward and there very few reasons to use a VOP SOP/Point Wrangle. The OpInput bindings alone have led me to prefer the AttribVOP.
Houdini Lounge » Triangulize with X method
- tjeeds
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eetu
In other software you would need to code your own plugin for this, or just make do without..
Unfortunately, it's already part of the toolset in most other softwares
The new geometry stuff in VEX is rad though!
Houdini Lounge » Triangulize with X method
- tjeeds
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Houdini Lounge » Triangulize with X method
- tjeeds
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Houdini Lounge » Triangulize with X method
- tjeeds
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Yeah, I would have thought that would do the trick too, it's supposed to anyway! I get 7 points out of the polyextrude, so the default consolidation gets all but one of the points. Looks like performance varies with orientation though, rotating it causes the point count to fluctuate between 6 and 8 points
Not a big deal I guess but kinda weird
Not a big deal I guess but kinda weird
Houdini Lounge » Triangulize with X method
- tjeeds
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Also correct, but you do have to raise the tolerance as 1e-05 is too small to do the consolidation.
Houdini Lounge » Triangulize with X method
- tjeeds
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You'd also need to append a Fuse SOP to consolidate the points, if you wanted to go the extrusion route.
Houdini Indie and Apprentice » new script question
- tjeeds
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What is the worst mistake ever made in computer science and programming that proved to be painful for programmers for years?
http://qr.ae/tLHCH [qr.ae]
http://qr.ae/tLHCH [qr.ae]
SI Users » Softimage to Houdini - Pros and Cons - What could be done?
- tjeeds
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takita
what I'd really like is to be able to pass a full 3x3 matrix (or 4x4, and disregard the translation) and have it displayed (similar to how you displayed it) as a tri-color axis (like we have in ICE) only without having to break it down in to vectors and create three separate attributes and add each of them to the display and then turn them on…
I'd love to see this as well! In the absence of offical support you could definitely accomplish this with some Add Point/Add Vertex nodes and then wrap it up into a VOP OTL so you can pop it down whenever/share it with your friends/collect all 4.
The other thing I really really miss from SI is getting stable solid orthonormal basis vectors from curves and polymesh faces for free. Would looove to have that…
Do you mean getting this data in VOPs? The PolyFrame SOP calculates these guys (in a variety of ways) and stores them as attributes that you can pull into VOPs.
Houdini Lounge » printing asset
- tjeeds
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You can use the opscript hscript command in the Textport for this. It prints out a list of nodes in a given network followed by their connections.
Houdini Indie and Apprentice » attribute create or point wrangler
- tjeeds
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VOPs is technically the fastest, though Wrangle nodes are basically just as fast (just a tiny difference). They both create vex code, if you look inside a Wrangle node you will see that it is actually VOPs under the hood.
If you're using $PT or any other value that varies among points then the AttribCreate will be much, much slower due to the use of hscript variables and expressions.
If you're using $PT or any other value that varies among points then the AttribCreate will be much, much slower due to the use of hscript variables and expressions.
Houdini Indie and Apprentice » attribute create or point wrangler
- tjeeds
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It depends on what you're doing but in most cases a Bind Export in a VOPs or setting via one of the Wrangle nodes is the fastest. If you need a uniform value across all points then an AttribCreate with a default value and Write Values toggled off will be faster.
Technical Discussion » Cvex Volume Procedural vs OpenVDB Rendering
- tjeeds
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Hey Frankie,
I think the best of both worlds is to use the same code in a Volume VOP and the surface shader. The SOP generated volume can be low res and it will act as a cacheable shading bound for your shader detail. Small changes in noise shouldn't require you to regenerate the cache either. It's not as elegant as using one or the other but I think it is the most efficient.
I think the best of both worlds is to use the same code in a Volume VOP and the surface shader. The SOP generated volume can be low res and it will act as a cacheable shading bound for your shader detail. Small changes in noise shouldn't require you to regenerate the cache either. It's not as elegant as using one or the other but I think it is the most efficient.
Houdini Indie and Apprentice » how to copy attrib of points to primitives
- tjeeds
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Point expressions are notoriously slow. It doesn't matter if you only have two points/primitives, but if you are dealing with larger amounts of geometry then using an AttribVOP will better serve you.
Technical Discussion » VDB Activate: Deactivate not working as expected
- tjeeds
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Technical Discussion » VDB Activate: Deactivate not working as expected
- tjeeds
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Hey Jeff, thanks for the reply. You are correct, dilation with a mask accomplishes the same effect as displacing in a volume vop. It is a bit more elegant than the activation/deactivation scheme, but you do take a performance hit.
I sent this issue to support as well and as it turns out the real trick here is to use a VDB Resample to rebuild the levelset after each iteration. When I introduced that into my setup there's actually no need for activation or dilation assuming a small enough displacement distance is within the starting exterior bandwidth.
I sent this issue to support as well and as it turns out the real trick here is to use a VDB Resample to rebuild the levelset after each iteration. When I introduced that into my setup there's actually no need for activation or dilation assuming a small enough displacement distance is within the starting exterior bandwidth.
Technical Discussion » VDB Activate: Deactivate not working as expected
- tjeeds
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I'm attempting to make an iterative levelset growth tool using a Solver sop and have run into an issue where Deactivation seems to stop working.
The first example in the attached file shows 3 iterations laid out and tied to $F, step through to see each operation. You can see that the Expand works correctly (though I wish you could limit it to exterior expansion only), but when using Deactivation it only affects the Exterior band. So each iteration the interior collects more and more needless voxels.
The second example shows what happens when a Volume VOP operation is applied after exapnsion and before deactivation. Not sure why but here deactivation stops working entirely.
I've tried clamping the output to the +/- background intrinsic and that doesn't seem to help. What I'd really like is for deactivation to respect the initial Interior/Exterior bandwidths, or to have parameters for them on the Deactivate tab. Anything above or below should get deactivated.
Any thoughts on what's going on here?
Is there any other way to control deactivation of voxels?
The first example in the attached file shows 3 iterations laid out and tied to $F, step through to see each operation. You can see that the Expand works correctly (though I wish you could limit it to exterior expansion only), but when using Deactivation it only affects the Exterior band. So each iteration the interior collects more and more needless voxels.
The second example shows what happens when a Volume VOP operation is applied after exapnsion and before deactivation. Not sure why but here deactivation stops working entirely.
I've tried clamping the output to the +/- background intrinsic and that doesn't seem to help. What I'd really like is for deactivation to respect the initial Interior/Exterior bandwidths, or to have parameters for them on the Deactivate tab. Anything above or below should get deactivated.
Any thoughts on what's going on here?
Is there any other way to control deactivation of voxels?
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