Combining Solvers With a Multi-Solver in Houdini

A cool thing that you can do in Houdini is to stack solvers with the help of a multi-solver. In this tutorial I'm showing a simple example of this by using a pop solver together with a bullet solver.

[@quentinrossetto1899]

5 years later and this video still helps me a lot, thanks !

[@quentinrossetto1899]

Still the simplest and most usefull ressource on multisolver as well, congrats !

[@aminebenafla]

simple and sweet ! i like that sometimes we can get soo lost inside Houdini about how we was build ( complexity ); but to get the job done can be more easier than we thought i dont mean i dont love the level of access to the data with it thats why i I threw my 8 years in 3ds max but i use to watch alot of tutorials ! that one its pretty sharp about specific question beside the fact to get the background ! you do a great job dude thanks !

[@aeko]

AMAZING video! Thanks so much for the super quick explanation. Simple and perfect! New subscriber. Please make more about DOPs like this!

[@edschiffer]

THANKS! That's exactly what I was looking for.

[@AnsonSavage]

I keep coming back to this video, so good!

[@ParticleSkull]

Cool stuff! Thank you

[@abstractwaves6166]

very good tutorial, short and straight to the point

[@Dominic-du4ow]

Simple and powerful. Thanks for sharing.

[@mohanpugaz]

Oh Man Very very useful tricks!. Thanks a lot!

[@TheKitneys]

Great stuff. Thanks for sharing your insight.

[@Sobieski526]

So simple! Thank you

[@rahulbisht396]

you always surprise me sir

[@PhilippPavlov]

Oh, so thats how it could be done... Thanks, very useful!

[@muhammetmertturan]

I LOVE YOU, thanksss. U R Amazinggg

[@traceurAlex]

super cool!

[@rickedeckard2006]

Many thanks for you time. Excellent tip.

[@massimobaita7178]

Thank You very much!

[@rileyman360]

quick question, after adding the bullet rdb solver into the multisolver, and making sure they're in the correct order shown here, I found that the objects don't follow the curve force I had drawn, however when I remove it, they follower the curve force exactly as I want them to. Any idea on what might be happening? The tutorial you've made is otherwise perfect and greatly appreciated.

[@tomjerry84]

I wanna give this a hundred Like

[@ChrisGray3d]

Very cool. Doing this in 17.5, the packed primitive 0 that comes out of the dopnet doesn't seem to be affected by the pop curve force. It just floats off. I'm deleting it with a blast, but I wouldn't mind understanding why this first cube is different. It's even created when I turn the particle generation off.

[@ShortSweet3D]

Hmmm, odd. I opened up my old project file and it seems like it still work in 17.5 for me

[@riccardobrunello2248]

really cool!!

[@ahahlex]

thanks !

[@saadomar1101]

i gotta thank you man !

[@Koba_K24]

This is wonderful but they're still intersecting because the geometry isn't following the rotation of the bullet solver's geometry representation. I haven't found a way to solve this yet and this is happening also in this video if you look closely... they're only partially avoiding each others.

[@dannyanalogue]

I have the exact same problem. Did you ever solve it?

[@anthonymcgrath]

loving these short tuts for you thanks :) any chance you could do one for destruction? I know there's a few on yt but maybe a 3 vid series.. propagate cracks.. controlling simulated pieces to a final rest position.. stuff like that?

[@ShortSweet3D]

Happy you like them! :) Sure, that's not a bad idea. I have a few others tuts I need to finish up first, but then I'll have go at it.

[@mrmaxim77726]

Це дивовижно! Дякую!

[@angosalvo5734]

I hope it's not too late to thank you for this :) If you're still around. Is there a way to modify the scale of objects along the curve based on their age ?

[@098765432qwertyuiop]

Entagma did a video on this some time ago, basically you need to trick the solver into thinking it's new objects @every frame (also this crashes a lot so beware) kzbin.info/www/bejne/oYvYoIOvgcidbJY And i;m not really sure of the usefulness of the popsource in OP's videos as you could just as well create a packedobject on everyframe and applying the popforce in the 3rd input of the Rigid Body Solver

[@angosalvo5734]

@@098765432qwertyuiop Thanks. Will check it out I've got I work around though for what I was doing

[@HangYuriYangFX]

I actually have a question... How to make pop interactive with simulated RBDs?

[@ichtreffnixtv8605]

Is there a way to scale the instances inside the dopnet? I'd like to decrease the scale over time based on @nage.

[@ShortSweet3D]

yes, set the packed transform with setpackedtransform() (or setprimintrinsic if you are on an really old version of Houdini)

[@ichtreffnixtv8605]

@@ShortSweet3D Thx for your reply, should I use a pointwrangle ? And where exatcly should I place it?

[@ShortSweet3D]

@@ichtreffnixtv8605 depends, I usually put it in a SOP solver and an attribute wrangle. I think Entagma might have done a tutorial about this a few years back that you prob still can find online

[@ichtreffnixtv8605]

@@ShortSweet3D Alright. Thanks for the answers ! :)

[@ichtreffnixtv8605]

Ok, I've managed to change the scale of the instances, even over time , however I can't control it. I actually have some sort of nage, which would let me map the scale with chramp(), but the problem is that there are always new instances being generated, and I permanently want to get the packed transform of the creation frame. This would be easy if all the packed instances were created at one frame, then I could just branch of with a timeshift and set it to creationframe, then wire it in my dop and read the packed transform, which would always be the initial packed transform. Then I could multiply that with my chramp() and I would get a clean control of my scale in the sim. I'm not sure if this is possible. Long story short; is there a way to store the value of the packed transform on its creationframe in an attribute? So something like this: matrix3 trn = primintrinsic(...).valueAtTime(@creationtime)

[@mathef]

Very cool tutorial! Thank you :) Can anybody help me with randomizing particle scales please?

[@ShortSweet3D]

Just put a wrangle right after the scatter node and type: "f@pscale=fit01(rand(@Frame),0.5,1);" The last two values are the scale range.

[@DommageCollateral]

hello!

[@christianbohm6118]

This is completely unnecessary. The POP Curve Force works with packed RBD directly.

[@BaconBlocks]

not completely, in this setup you're able to continuously emit rbd objects

[@christianbohm6118]

@@BaconBlocks You can continuously emit RBD objects. Not very hard.