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Growing icewall


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Hi good houdinifolks.

Im currently doing some test on how to create a growing icewall that looks real or close to real.

I was wondering if anyone of you have had the same challenge and would care to

share some basic ideas.

I have two approaches. One is involving particles with the fluidmesherSOP. It gives

a nice effect, but it becomes to heavy if I want some more volume.

The other is using a isoofsetSOP on a bunch of boxes that slowly gets thicker. It gives me

the volume I want but it doesnt look that convincing.

I attaches the two examples.

any suggestions or ideas would be much appriciated.





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I think different approaches are possible depending on what your wall needs to do.

If is just a rectangular box then you could use animated extrusion or animated peak sop.

If you want more irregular growth patterns I find that you somehow need access to the state the growth was in at the previous frame. This kind of feedback loop works well using the sop solver. You might want to have a look into aggregation systems or L-systems for more complex patterns. I also think you need to define a difference between surface ice (like frost flowers) or a full wall of solid ice (The example from one of the x-men movies jumps to mind - perhaps you can research into that to figure out how they did it). As surface ice is more a shader level displacement implementation and solid ice is geometry level.

The problem with using the isooffset is that jitter you will get when you feed in deforming input geometry caused by the interpolation in the isoofset. You can turn up the resolution but it will slow down your scene a lot.

I recently did a test in which I did the exact opposite (rather than growing, you erode a surface away - you could consider running that sort of operation backwards, so it accumulates over time.). (see movie) That uses the sop solver and links in point attributes with the shader to get displacement at render time.


Edited by pclaes
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Hi Peter ,Alonzo and Dan.

Thanks for your comments - Much appriciated.

Peter you are right about the jitter on the isooffsetSOP - Its a bit of a problem.

I did some other test on growing icecrystals with particles and I have gotten some good results so far.

Not perfect or anything like a complex naturlike simulation.

I also did some test with L-systems for growing icecrystals, but I havnt gotten deeper into it.

But my goal was to create somekind of larger icevolume that got thicker and thicker. The approach

with the SOP solver looks great. Ill give that a shot.

The shader is the standard glasshader with a little bit of displacement on.



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