Hello dear Houdini community,

I ran into this issue multiple times now, and was wondering if it's me doing something wrong or if its an expected result.

Basically I'm creating a curve, modify its shape, and then copy & paste it many times to achieve a grid-like structure using said curve.
Curve > Mirror > Join > Convert(toNurbsCrv) > CopyAndTransform > Join (> CopyAndTransform).
However, as soon as I enable Join, the curves break noticably, showing up as if the calculations/nodes are not working. I'm following different kind of tutorials node by node, and it's working for them (this one from Entagma for example: https://youtu.be/C9VBY9Wbbrw?t=322).


The moment I disable the Join node, everything works again.




When I bypass the node or use Labs > Reset Viewport, the broken areas change - in some places it fixes a previously broken area, but new broken areas appear. Below this post, I've also attached a recording of me toggling the "bypass" button many times until it appears "fixed" (temporarily, breaks the moment I recalculate the nodes).


Would someone be able to tell me what's going on here? I would love to find out how to fix/avoid this.

Thank you in advance for your response.

Kind Regards,
Thomas

A hip file would be a whole lot easier to diagnose tbh.

I don't seem to be able to replicate the issue seen here.

(Attached) a basic curve setup for a weaved material effect, .

Thanks for your response and taking the time to try to replicate the issue on your side.
When I open your hip file, I immediately get the same issue again (just by toggling the nodes).

I've attached a hip file below that shows the errors for me.

I just toggled the nodes on my hip and your debug_00 multiple times each to make sure, I cannot replicate
the viewport glitch you are getting....I bet that sounds familiar for many contacting the Sidefx bug report team

What version of Houdini are you using?

What graphics card / drivers do you have? .....running Vulcan or OpenGL viewport?

I can say for 100% fact after upgrading my PC which had a very old gtx1070 to something much more modern the amount of
little glitches and issues it resolved for me was/is very noticeable, maybe that could be your issue?

Try running Houdini with the older OpenGL viewport by adding:

HOUDINI_VULKAN_VIEWER=0 in the "houdini.env" file found in " C:\Users\*yourname*\Documents\houdini21.0 on windows
or set it in Environmental variables.

You could also try deleting/renaming the folder mentioned above and start Houdini which will create a "new"
folder with all default settings which very often will fix Houdini when it gets unpredictable and sometimes stops playing nicely.

Oh hmm thank you for the confirmation EZiniT.

I'm using Houdini version: 21.0.512
My gpu is: Nvidia RTX 3090
I just installed the latest gpu driver a minute ago (unfortunately no improvements).
I added "HOUDINI_VULKAN_VIEWER=0 " to the houdini.env. Now I opened the files, and to be safe, I started over and recreated the same node network - what can I say, it works!
I guess it was the Vulcan viewport, seems like OpenGL made the difference.

Thank you so much for your help EZiniT, I couldn't think of any options anymore on my own.

Really appreciate it, thank you!

The RTX3090 should more than meet minimum requirements for H21 and the vulkan viewport, using openGL loses
some of the nice touches H21 brings.

I would definitely update your version of 21.0.512 to the latest daily build which is 21.0.603 and try
vulkan again, that's a hell of a lot of bug fixes/updates since the version you have, the issue may be resolved already.

If that still doesn't fix it then send in a bug report to SideFX.



Cheers!