Hey all,
I’m playing around with a very basic smoke sim, that follow a spline, i can get it to work fine but when i add cutter geom it fails to follow the path and just smokes around the top of the emitter…
the cutter is just a sweep on a copy of the path that has been shelled and collapsed to form a pipe…
any help is greatly appreciated.
Thanks.
Hey,
Do you want the cutter to interact with the simulation or you want to use it just for the rendering ?
If you need it only for the rendering you can right-click over it and from the Phoenix properties set it to Non-solid or exclude it from the sim from the Scene interaction rollout.
I just want to restrict the smoke to be inside the pipe…
it works without the cutter geom but when I enable it in the rendering rollout the smoke doesn’t follow the path…
I really appreciate any help!
Thanks
Hey,
When you right click on your cutter geometry, is the Solid option unchecked? If it’s not, it would be an obstacle to the fluid simulation - please uncheck the Solid checkbox 
Cheers!
Hey mate,
I tried it (unchecking solid object) but it doesn’t “force” the smoke to stay within the piping… it behaves like its (the cutter geom) not there at all…?
Ah yes - the render cutter just ignores parts of the fluid at render time.
Sounds like you might be trying to add an obstacle to the simulation after all though, do I understand you correctly?
Can you show some screenshots of your setup, so we can be on the same page?
Ah - if you want the pipe to collide with the smoke you will need to have the solid checkbox turned on.
Then in order to get proper collision with the smoke - make sure that the pipe has some thickness (at least 2-3 voxels) and your grid resolution is high enough.
Then if it is still not working correctly - try to invert the normals of the pipe.
Cheers!
Did you try my suggestions from above? Inverting the normals for the pipe should be the way to go.
yeah mate i did and nothing happens at all, ie. it doesn’t generate any smoke…?
Can you attach the scene so we can take a look? It needs to be zipped in order to work with the forum attachment system.
Thanks!
Hey,
I just took a look of your scene and I’ve noticed that the spline called “shape_cutter” is a Solid Object and it is stopping the smoke to reach the following path.
If you uncheck the Solid Object checkbox for the “shape_cutter” spline, the smoke should start following the path.
Hope that helps!
thank you mate, I appreciate the help…
so anything can get in the way, even if just a spline and not selected to interact with the sim…?
Everything interacts with the sim by default - if you want to leave something out, you can exclude it from the Scene Interaction rollout
Thank you so much, you’ve (all) been a wonderful help!
Hey, some more news - since tomorrow’s Phoenix 4 3ds Max nightlies, splines will not interact with the simulation unless you explicitly extrude them
