SOP Solver for Beginners in Houdini

If you want something to grow over time or maybe shrink over time, SOP Solvers make it easy. SOP Solvers are perfect for animations where you have an object evolving over time, from frame to frame. I create a footprint scene with a Height Field terrain.
Download Houdini File:
bubblepins.com/blog/sop-solve...
Download Houdini File with New if Block Node:
bubblepins.com/blog/if-block-...
Math Explanation of Sine Wave:
bubblepins.com/blog/sop-solve...
Math Explanation of SDF Detect Collisions:
bubblepins.com/blog/sdf-signe...
Math Explanation to Calculate Displacement:
bubblepins.com/blog/sdf-used-...
#houdini
#sidefx
#physicalsimulation

[@aeko]

This is an AWESOME tutorial! Very well explained. Thanks so much for uploading, exactly what I was looking for!

[@yaroslavhoncharenko106]

Hello) Your tutorials are beautiful! I'm happy to find you^^

[@emepicuta3899]

This sort of vids its what makes learning vfx so amazing. Your videos are so important for a proper understanding of houdini. THANK YOU very much. For real. Be very proud of this work. You are a very talented teacher

[@bubblepins]

Thanks for the generous comment!

[@litote9]

Another detailed tutorial. Much apreciated!

[@bubblepins]

Thanks!

[@massimobaita7178]

Thank You very much!

[@clemlysergy3335]

Another great tutorial, thanks! BTW a good way to get around the issue with the solver display updating is just to pin the Scene View before going into the solver.

[@bubblepins]

THanks! I never knew that!

[@FeatherandtheWind]

Thanks. Very complex. Watched it twice. Still not sure if I understand it all.. but good. Excited for the next one

[@bubblepins]

Thanks for watching! If you have any questions, try asking them in the comments, I'll try my best to answer them. The next one is coming soon in the next few days. I just finished a couple rounds of editing, I just need to polish it up with one more round of editing. It'll be about Vellum sims.

[@irql2]

Subscribed!

[@carlherner9458]

hey this is amazing for someone coming from blender and starting houdini like me! If I can make a wish I would love a Vellum for Beginners video :)

[@bubblepins]

Ur wish will be granted! But it'll probably be next week. I'm currently recording the disintegration and growth videos (its the last 20 sec scene in this video as a preview) I have always had vellum in my head. I always wanted to do a clothing design for a character. But I think you want a Vellum sim tutorial? Like a balloon or some sort?

[@carlherner9458]

@@bubblepins wow super:) yea I was thinking of funny vellum sims (im more towards motion graphics etc), so yeah a balloon would be really great to watch! Of course vellum sims can include cloth/characters and so on aswell! Depends a bit on how indepth you go, and if you do 1 longer or multiple smaller examples etc!

[@psychedlicavfx6646]

@@carlherner9458 I posted one recently on my channel, vellum balloon inflate and pop.

[@carlherner9458]

@@psychedlicavfx6646 cool! ill check it out, subscribed!

[@psychedlicavfx6646]

@@carlherner9458 awesome!

[@regularmenthol]

This is actually the Solver SOP. The SOP Solver is a DOP node that allows you to evaluate SOPs in DOPs. It's an important distinction! I found this by accident while looking for tuts about the other node

[@bubblepins]

Yeah I realized I had misread it after I made the video. I did make a short video explaining the difference between the two later on.

[@regularmenthol]

@@bubblepins don’t worry, you’re not the only one to have mixed it up!! Glad you caught it :)

[@allenzhang1824]

Thank you for your detailed share! As a totally new user to houdini, i'm glad to meet such a nice tutorial. But when i test this mode in different parameter, such as set translate of torus to "-8*(abs(sin($FF*5)))", which make torus go deeper, so odd happen in the gird_object. Is that because the deformation more than the model can bear?

[@bubblepins]

Hi, the -8 makes it go deeper because the negative flips the sine wave and the 8 makes the amplitude larger and also the abs() function cuts the sine wave in half so you only get the dips. Sorry hard to explain in text, I hope that makes sense. I have a blog post explaining this picture by picture starting with sin(x) = y and for each step I draw the sine graph: bubblepins.com/blog/sop-solver-in-houdini I hope that helps!

[@allenzhang1824]

@@bubblepins thanks! i've understood!

[@felixbaker3160]

Thanks a lot for this Tutorial, it was really helpfull! I‘m wondering if its possible to achieve the same effect but with the torus being deformed as well? For example if a plane crashes into a soft ground and both of them gets deformed? Couldn’t find any information or tutorial to achieve something like this

[@bubblepins]

You can try a different approach in achieving that, which may be a bit easier to use H19's Vellum Shape Matching to deform 2 objects crashing together: kzbin.info/www/bejne/noXJnqefr56kias Or you could use a more complex method that I have shown in the past with SDF Destruction: kzbin.info/www/bejne/l2nbeZuge8qNhJI Using the Solver SOP method shown in this video can still work, but I think when you have 2 objects that need to deform at the same time, it may get complicated with using the Solver SOP. Hope that helps!

[@ProfessionallyIncorrect]

I've tried to remake this using the new if/end nodes for the whole thing, but can't get it for some reason. Have you had any luck recreating the old if vop node using the new if/end block nodes?

[@bubblepins]

this example comes from the SOP Solver examples, "Footsteps". Are you trying to recreate the functionality using the new updated VOP & if blocks?

[@bubblepins]

Hi I came home and gave converted the old if block to use the new if block in Houdini 17.5 in the Footsteps project shown in this video. It's super rough, because I did it super quickly. I will repost a cleaner version of the project file a little later. I hope this helps. bubblepins.com/blog/if-block-new-updated-if-block-in-houdini-17-using-sop-solver-footprint

[@smyrkphace]

When Im inside a sopsolver in a dopnet, I cant see anything Im working on. Is that normal? I mean it works fine when I get out, but nothing shows up inside.

[@bubblepins]

I think you're referring to the viewport that you can't see anything on the viewport like the simulation or anything. It's because the sopsolver inside the dopnet requires you to cook the simulation first, just cook a few frames. Then go inside the sopsolver, you'll see something on the viewport. I believe the sopsolver only works on cached data, that's just my suspicion. Hope that helps!

[@smyrkphace]

@@bubblepins Thanks yes thats it

[@ric_-1022]

I did not understand what "up vector" stands for, thanks for the tutorial.

[@bubblepins]

Sorry for the late reply, for some reason UT didn't send me notifications for some of the comments. The up vector is used to denote how the object is standing. What is the object's upright standing position. Because the object could be like on its side or something.

[@user-rp6qr3by5y]

wonderful i am from china and i like video comeon！！！

[@user-xjcltmddn]

Isn't it different between solver sop and sop solver dop nodes? Thanks to the video, I knew perfectly about solver sop. But I want to know about what is sop solver. Because of this, I can't move on to the next topic. Please......

[@bubblepins]

Are you referring to the sop solver node that you get inside a dopnet? The functionality is the same, except the data you get from the previous frame is the simulation data. Hope that helps.

[@user-xjcltmddn]

@@bubblepins Oh, it's the same function. Thank you!

[@brettchassen2888]

Oh my if thats a 'beginners' tutorial on sop solvers i'd hate to see an advanced one lol....this makes houdini look very very scary lol

[@starwarz8479]

Great video! What other languages do you speak?

[@bubblepins]

English is my first language. I don't think I qualify to do tutorials in other languages, but it's something I have thought about. And maybe one day I'll learn another language just to do a tutorial in it!

[@starwarz8479]

@@bubblepinsGotcha, I'm trying to create something like this, swrily and bubbly paint or ink-like liquid expanding and contracting. What would be the best approach to create it? Particle fluid or pyro maybe? www.shutterstock.com/video/clip-1033586267-1920x1080-25-fps-very-nice-abstract-colors www.shutterstock.com/video/clip-1026885683-1920x1080-25-fps-very-nice-abstract-colorful

[@ihorkarpiuk4102]

hard to believe that it's not on the SideFX page

[@bubblepins]

Thanks!

[@rahulrawat952]

tried so many times in houdini 18 .. dont know why im not able to do it :(

[@bubblepins]

Could you describe a little about your issue? Maybe I can help.

[@rahulrawat952]

@@bubblepins i wached the video few times and tried it by my self.. But failed. Than i mached every node and setting.. Seems fine but definately somewhere doing worng.. I will try again one more time :) Thankyou so much .. You explain very good.. Helping us for free.. Giving your valauble time .. ❤😊

[@bubblepins]

@@rahulrawat952 Try to setup the VOP SDF stuff in a new fresh scene WITHOUT the sop solver. You can manually move the torus using a transform node to test if you have the VOP sdf stuff setup correctly. Then if you can get that working, then put it into a sop solver. This will it will make it easier to debug by separating it into two different steps. Hope this helps!

[@rahulrawat952]

@@bubblepins yes i will do Thankyou so much 😊😊😊

[@bubblepins]

@@rahulrawat952 welcome! Have fun Houdini-ing!

[@eric3020]

Great Tutorial like always! However the example is outdated. The Vop SOP inside the solver is not the best way to do it - I just used a point wrangle with this expression, nice and simple: float vol = volumesample(1,0,@P); if (vol < 0) { vector offset = set(0,vol,0); @P += offset; }

[@bubblepins]

Nice. That works too!

[@Fleischmahn]

This is not a SOP Solver, this is a Solver SOP... A SOP Solver exist within a DOP context. Sorry for being picky, but it might be unclear to some.