melting a hard edged object

   5861   7   2
User Avatar
Member
345 posts
Joined: June 2008
Offline
Hi everyone. Happy new year!

my name is Thanassis and I'm doing the C4D Houdini Engine Support in another part of this forum.
I have a general Houdini question.

I was experimenting with the “Melt Object” shelf tool, and I couldn't find a way to retain the detail of the original object.
The SideFX tutorial was very general and only showed how to melt the object NOT how to control it thereafter, or solve problems like this.
When using a VDB workflow, the Convert VDB node has the second input to allow you to define parameters from the original object, thus keeping feature sharp e.t.c. (Compute Vertex Normals, Transfer Surface Attributes, Sharpen Features)
I can't seem to find any equivalent when using the Melt Object Shelf Tool.

Is there a “standard” (and hopefully easy) way to setup a hard edged melting object and retain the model accuracy for the non melted part as close as possible, or do I need to setup an elaborate network?

Mind you, I am a novice so please presume I only know the very basics :-)

Cheers
User Avatar
Member
2537 posts
Joined: June 2008
Offline
Have you checked out Ben's tutorial on the subject?
https://vimeo.com/122217238 [vimeo.com]
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
User Avatar
Member
345 posts
Joined: June 2008
Offline
Enivob
Have you checked out Ben's tutorial on the subject?
https://vimeo.com/122217238 [vimeo.com]

Oh, yes. Not only that, Ben's tutorial inspired me to create a totally different melting asset that uses TP inside C4D to melt an object. It was part of my C4D - Houdini Engine presentations.

To be honest, melting objects like that is fairly easy, once you understand some Houdini fundamentals, but the problem I'm trying to solve isn't addressed.
The Angel loses its definition because we are converting a mesh to a volume.
For “organic” structures that's fine, but if you are trying to melt a “metal H-beam” for example, that method doesn't retain the solid hard edges.
I have a general idea how to solve the problem, but that requires quite a lot of work:
Convert the solid into a VDB volume, and use VDB clip to subtract the melted portion. Then use the Convert VDB second input to sharpen the features.
The part that melts would be a separate SOP… etc etc.
And I still have no idea how to make the H-Beam bend when it get's too thin.

I was wondering if there's a specific way we can do that as part of the Melt Shelf tool, or something similar.

Cheers
User Avatar
Member
13 posts
Joined: May 2015
Offline
Hmm, I would do my simulation as usual but then use the points from the sim to move the vertices of the original h-beam object and blend it with the fluid sim.
Don't forget to turn off reseeding to get constant points.
User Avatar
Member
345 posts
Joined: June 2008
Offline
Hampus Hedberg2
Hmm, I would do my simulation as usual but then use the points from the sim to move the vertices of the original h-beam object and blend it with the fluid sim.
Don't forget to turn off reseeding to get constant points.

So, to make sure I understand, I need to have the original model highly tessellated to begin with, and after the initial movement of the Original vertices, I blend with the sim…
Aha… nice idea!

Thanks for the reply.
Cheers
User Avatar
Member
13 posts
Joined: May 2015
Offline
Yes, exactly.
It's quite easy to do interesting things with the deform points node. For example, depending on what your deformation should look like you can use a low res version that in turn deforms the highes version smoothly.
User Avatar
Member
74 posts
Joined:
Offline
Interesting…
How would you blend between the the original geometry and the fluid sim?
In compositing or in 3d?
User Avatar
Member
13 posts
Joined: May 2015
Offline
Either or. But if doing it in 3D I would use VDB blend/morph.
  • Quick Links