Random partikel experiments

In case anyone wants to start using Houdini Engine for things. You can check out this quicktip I made where I make a 3d text generator from scratch. Including the things I wondered about when I started using it: How do I get it into unreal? How do I update it? and How do I bake the asset out?

https://vimeo.com/212456354

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A while back I held a presentation at the End User Event. Itā€™s now up and live!
In it I talk about how Iā€™m updating my workflows and I also do a live demo using Houdini Engine in Unreal to create Glowsleeves.

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This is great! The impostor particles are probably much cheaper than a vertex anim solution. Thanks for sharing!

This is a work in progress of a cheap volumetric blood effect that hopefully will make it onto the marketplace soon. Currently focusing on getting the shader right. Tricky since I want to keep it fully opaque for performance but Iā€™m getting there.

The effect is currently using 6 particles. Right now itā€™s also using two textures But they will be combined to one 1024 texture eventually.

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So youā€™re basically reducing the ā€˜massā€™ off the blood particles to 0 to fade them out by using vertex animation?

No, there are 4 different vertexanimations playing in there. I made them disappear by eroding the actual VDB so I donā€™t have to worry about them popping away midair. At the end of the sequence they will always be dissolved more or less naturally. Itā€™s hard to see in this omni clip as I was only testing the shading. Iā€™ll post a directional version soon where itā€™s easier to see the benefit of it.

Nice! Liquid spurts are really cool. Really looking forward to seeing what more you can show of this. Are some of the particles axis locked?

No, but they are meshes so they arenā€™t billboarding or anything. The above example had random initial rotation set in all axis and then set free into the world to do their thing! (Well, for about half a second before they die.)

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Iā€™m starting to get some variation in there. Still blocking in the shapes I want, but I think itā€™s starting to look nice and thick now :slight_smile: The directional spurts need more love though.

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Now we are getting somewhere. Playing with additional elements and different sizes. Still somewhat sluggish, but itā€™s going in a direction I like. Itā€™s a shame the compression doesnā€™t show all the nice reflections on the blood. Iā€™ll have to do a high-quality recording once itā€™s done.

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Lookin good!!!

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Nice Blood FX,

Do you consider refraction or SSS? I just wonderā€¦
And erode actual VDB, I usually decrease ā€˜Droplet Scaleā€™ in ā€˜Particle Fluid Surfaceā€™ node in houdini.
But It makes some flickering in mesh. How did you solve this problem?

Thanks! I tried both. SSS gave me some interesting color shifts, but not enough to warrant the extra cost. I got similar result by fresnel lerping between two colors. But I decided against that as well becuase it gets unpredictable in certain lighting scenarios. I may try again once Iā€™m happy with the effect.

Refraction didnā€™t look great since it was too uniform. If I baked out velocity colors or something to drive the refreaction it might be interesting, but without it, it just looked bland.

I didnā€™t solve the flickering. The actual vdb erode is quite stable so most of the flickering I get is from the polyreduce. Once the mesh becomes too detailed, itā€™s hard to keep the topology consistent, and then I get flickering faces/normals.

Right now Iā€™m trying to solve it by blurring the normals, but Iā€™ve also experimented with transferring the normals from the highres mesh. Still some problems to solve. Most of the time though, the effects are too fast for it to be an issue.

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Oh man, Thanks for your kind comment =)

Youā€™re doing so many R&D!!
I look forward to seeing your final shot.

Iā€™m afraid the final shot will be underwhelming. Iā€™m doing this for an assetpack so everything is kept generic. For a regular production I would be able to make it better by customizing it to the intended use.

According to your previous works(Battlefield series)
I donā€™t think your final shot looks underwhelming =)

Iā€™ve added some continuous gashes and started working on some decals to go with it all. Oh, I was told that the music was too murdery, so I changed it up a bit :stuck_out_tongue:

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Started working on a blood pool shader. I canā€™t seem to find a way to blend between the surface normal and the ā€œdeepā€ part. The movement is working alright at least.

Editing this post to limit spam.
Iā€™ve recorded a slowmotion version to show a bit more detail of how the vertex animations work.

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Added in global color overrides. Working quite well :slight_smile:

INSTANT MONSTER BLOOD!

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Inspired by Klemen Lozars tweet showing his awesome setup for lightning arcs (twitter.com/klemen_lozar/status/942104101604560896) I decided to build a quick tool that would generate this kind of meshes. After this the remaining steps would be to generate a bunch and give them all a vertex color.

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