The parameters on the TopoBuild SOP are used to record what you did in the viewport. Since you moved a component in the viewport, the tool updated the TopoBuild SOP's parameters to describe this action.
Use the state's parameters (at the top of the viewport) to specify what kind of task you wish to perform, not the SOP's parameters.
Found 216 posts.
Search results Show results as topic list.
Houdini Indie and Apprentice » Trouble with the Topo node
- derrick
- 327 posts
- Online
Technical Discussion » Houdini Crashes on Alembic export.
- derrick
- 327 posts
- Online
Thanks for the example file. This bug was fixed for Houdini 16.5.329. You can install a recent production build (or daily build) to get the fix.
The “Support -> Report a Bug/RFE” menu item at the top of our web site can be used to file bug reports.
The “Support -> Report a Bug/RFE” menu item at the top of our web site can be used to file bug reports.
Technical Discussion » Houdini Crashes on Alembic export.
- derrick
- 327 posts
- Online
Technical Discussion » Wiresolver & orient
- derrick
- 327 posts
- Online
If I understand what you are trying to do, the initial orient values do not match what you want them to represent. The Copy SOP applies the minimal rotation to align the geometry's Z-axis with each template point's normal but you want the orient values to reflect the rotation described by /obj/coil/transform2.
Disconnect the transform2 node then place it between the copy1 and OUT_wire nodes. This will cause the rotation to be applied to the orient values as desired.
Disconnect the transform2 node then place it between the copy1 and OUT_wire nodes. This will cause the rotation to be applied to the orient values as desired.
Technical Discussion » Alembic Layering in Houdini
- derrick
- 327 posts
- Online
Houdini 16.5 uses Alembic 1.6.1. Houdini 16.5 does not officially support Alembic 1.7 but some experimental work is available in a feature branch of the HoudiniAlembic repository. It should be possible to merge this branch with the main Houdini16.5 branch and build a new plug-in but keep in mind Alembic 1.7 support is still at an experimental stage so expectations around stability, compatibility, and support (or lack of it) should be set appropriately. The goal in releasing an experimental feature branch is to let anyone interested in future Alembic 1.7 support (and are comfortable trying experimental code) have an opportunity to provide feedback and improvements.
Houdini Lounge » UT_QuaternionT lerp incorrectly
- derrick
- 327 posts
- Online
rash
Hey derrick, thanks man! how I find short path? with dot? I use interpolate like weighted sum, when I have Q1…Qn, where weight w(1..n)==1, what I need to do to find short path between several quaternions and do interpolate correctly?
If you are just considering a pair of quaternions, you could use a test like this to tell if they are more than 180 degrees apart: (Q0 * conjugate(Q1)).w < 0
It is less clear what kind of result you are expecting when you have multiple quaternions. Weighted sums of quaternions might not produce the behaviour you expect (you are delving into an area with lots of subtle complications). The idea of shortest path is not so clear in this situation. If your use case has a natural reference orientation, you may want to consider using that as a hint on how the interpolation should proceed.
Houdini Lounge » UT_QuaternionT lerp incorrectly
- derrick
- 327 posts
- Online
rash
Hey guys, could you help me please, why UT_QuaternionT lerp work incorrectly? What I mean, if you look picture, I do linear interpolate quaternion between two object, first object red rectangle second blue rectangle, so green object rotated between them…. so… problem is when I make angle 210, the green object rotated by long angle… If I use UT_QuaternionT.interpolate() it work correctly… but I need lerp, how I can do linear interpolate correctly?
Thanks!
You are likely providing lerp() with quaternions that are further than 180 degrees apart (remember two quaternions may effectively describe the same rotation but still be a large distance away from each other on the four dimensional surface). Since you want to find the shortest path, you should modify the input quaternions (multiply one of them by -1) so they are no further than 180 degrees apart (of course, this should only be done if your inputs are more than 180 degrees apart).
Edited by derrick - March 5, 2018 11:00:31
Technical Discussion » Wiresolver & orient
- derrick
- 327 posts
- Online
How is the value you are wishing to obtain different from the “P” attribute? Could you post an example .hip file?
Technical Discussion » Wiresolver & orient
- derrick
- 327 posts
- Online
I think I now understand what you are trying to do. Since the original geometry does not contain an “orient” attribute, the Wire Solver assigns a default value (the identity rotation) which isn't aligned to your geometry on most frames. You should provide an explicit “orient” attribute (see /obj/example/attribvop1 in the attached example).
Technical Discussion » Wiresolver & orient
- derrick
- 327 posts
- Online
The orientation of each point in /obj/geo1/dopnet1 can be read from the “orient” point attribute. The attribute value is a quaternion describing how the geometry has rotated relative to its rest pose. /obj/geo1/copytopoints2 uses this attribute to orient each control.
Technical Discussion » Topobuild geometry problems
- derrick
- 327 posts
- Online
How were the polygons with incorrect windings generated? Were they created with TopoBuild's new “Skin” mode or manually created with TopoBuild's “Build” mode? Do you have a reproducible scenario that results in TopoBuild creating polygons with incorrect windings?
Houdini Indie and Apprentice » Wiresolver - stick/stop on collision
- derrick
- 327 posts
- Online
Consider a procedurally built constraint network that pins the points you want to stick.
Edited by derrick - Dec. 4, 2017 19:14:44
Technical Discussion » Exporting Alembic Problem
- derrick
- 327 posts
- Online
Technical Discussion » Wire Object - selfcollision disabled when setting some value for the nocollide parameter.
- derrick
- 327 posts
- Online
Technical Discussion » Export Alembic Face Sets
- derrick
- 327 posts
- Online
Could you post an example Alembic archive from C4D and a .hip file illustrating how you are attempting to re-export the data?
Technical Discussion » Alembic Face Sets exported randomly
- derrick
- 327 posts
- Online
It looks like 3ds Max cares about the order facesets are defined instead of identifying them by name.
Facesets are represented in Houdini as primitive groups. However, Houdini's geometry model does not preserve the ordering of groups so the ordering is lost and it looks like this confuses 3ds Max.
We made a change to the Alembic ROP in Houdini 16.0.696 so it will create facesets in sorted order. We think they should now be exported with an ordering that 3ds Max expects.
Facesets are represented in Houdini as primitive groups. However, Houdini's geometry model does not preserve the ordering of groups so the ordering is lost and it looks like this confuses 3ds Max.
We made a change to the Alembic ROP in Houdini 16.0.696 so it will create facesets in sorted order. We think they should now be exported with an ordering that 3ds Max expects.
Technical Discussion » Normals off on alembic export to Unreal Engine
- derrick
- 327 posts
- Online
I suspect you are trying to export a collection of Packed Fragment primitives (or Packed Geometry primitives) for your object. This will result in a shape for each piece in the resulting Alembic archive. The warning is likely because you didn't specify a unique name for each piece so the Alembic ROP renamed some of the pieces. If you want a single object with deforming geometry, consider inserting an Unpack SOP before rop_alembic1.
The unexpected shading is likely a different issue. If you re-import the Alembic archive into Houdini, does the shading in the viewport match your expectations?
The unexpected shading is likely a different issue. If you re-import the Alembic archive into Houdini, does the shading in the viewport match your expectations?
Houdini Indie and Apprentice » Hair Collisions
- derrick
- 327 posts
- Online
shaneroshea
Hello! So I have hair on my character made, and the typical guide curves controlling the shape and are dynamic as a wire solver. However currently the wire solver is working just fine but when I make the animated geometry a deforming or RBD object and try to run a flipbook the computer instantly hangs and can't handle the calculations.
Is there anyway I might be doing something wrong? I'm new so this clearly must not be the most optimized method but as usual I can't seem to find enough documentation on how to get hair collisions to really get started so if anyone has any good sources I'd also take that!
Thanks so much for your time as always!!!
Is the number of curves being sent to the wire solver changing over time? Providing a non-animated “rest” attribute may fix this problem.
Technical Discussion » Alembic_In sourcecode || userProperties read
- derrick
- 327 posts
- Online
Source code for the Alembic support is shipped with Houdini. It can be found at: $HFS/houdini/public/Alembic/HoudiniAlembic.tgz
Both the Alembic SOP and Alembic Archive Object have parameters called “User Properties” that control what is done with the user properties.
Both the Alembic SOP and Alembic Archive Object have parameters called “User Properties” that control what is done with the user properties.
Houdini Indie and Apprentice » Alembic Scene Import , selecting primitives 'disabled'
- derrick
- 327 posts
- Online
The unpacked geometry is likely a single polygon soup primitive. Consider appending a Convert SOP to convert it to polygons.
-
- Quick Links