Houdini Tutorial - Bubble inflation

Source files available on timvanhelsdingen.com/vellum-b...
Hey guys! been a while, but here is a new tutorial.
Also wanted to take this opportunity to promote the patreon account that I just made, this is where you can find a collection of all my tutorials from now on and where you can also download the HIP file for this project (as a $5+ backer)

[@richnosworthy2497]

Really great Tim, thanks so much

[@MESHQuality]

Thanks Tim!
That was awesome.

[@DimaShishkov]

Very interesting tutorial. Thank you very much. A lot of useful tips.

[@mdsanima]

very nice stuff here! thank you so much!

[@AdrienLambertvfx]

Great tutorial ! thanks !

[@aboldmule]

Thank you, great tutorial

[@arbikerimov]

Thank You so much!

[@ebimol]

thanx, very useful and practical!

[@ahmed_5g]

thanks man that was helpful

[@dongjoonhan3179]

So much Thanks!

[@zhungbob9906]

nice work

[@Paul_13h37]

Hello Tim, Thank you very much for this tutorial. I've a question? how do you carve letters or shape into the bubble i've try with an attribute from map but i can't understand where i need to feed it? Or maybe using some substract operation in the vop attribute node to mask the noise? but since i'm very new to houdini (comming from c4d and maya), i cannot find the good setup! thank you very much if you can explain that to me (even if you can't thank you very much)^^ see ya mate!!

[@floriswildeman144]

leerzame video man!

[@lemmonsinmyeyes]

Hello, thanks for the tut, has the voroni fracture changed since you released this tut? When i follow it adds back faces and the breaks the poly extrude

[@kylejennings819]

for those stuck wondering how you promote a variable.... its done by clicking the middle mouse.

[@lalamax3d]

Hi Tim, thanks for tutorial, i am stuck at 16:00 approximately. SOP solver in Dop network isn't working. i tried to debug but simply with 'ConstraintGeometry' Data pipe, its not fowarding vellum constraint values. any ideas.?

[@HangYuriYangFX]

Very cool idea. Have you tested it on an animated object for this?

[@TimvanHelsdingen]

No, but should work fine as you can pin points to animated geo with vellum.
Or else you could always just point deform it.

[@alexanderhahn2812]

thank you for the amazing tutorial, unfortunately the link of the file is not valid anymore. is it possible to update it?

[@msistema]

Thanks for the tutorial, learned a lot!
But i have a question, i try to pipe in a collision geometry so the bubbles don't get inflated in certain areas to reveal some kind of form.
I know i can pinpoint more point so they don't get inflated at all, but i'd like for the bubbles to get inflated just until they collide with whatever object. You know why the collider object is not being recognized at all?

[@TimvanHelsdingen]

hey man! Glad you like it.
How is your collider setup? Vellum uses surface collisions. By default if you put a collider object it will be set to volume collisions. Let me know if that solves it. Cheers!

[@msistema]

@@TimvanHelsdingen Thanks!! I'm such a moron, i just used the surface collider shelf tool and it worked. Thanks and keep up the amazing work :-)

[@denitsabaycheva2311]

This is really a good tutorial, thank you very much for doing it! I was wondering...I need to make constantly generating spheres that inflate at random time, something like bubbles of a soapy foam...is there a way to change your setup to accept all the new generating spheres?...I know that vellum doesn't like changing geo, but your tutorial is so close to what I need to do, that I decided to ask :)

[@TimvanHelsdingen]

you can instance vellum into a sim,you can input points on the vellum source and it’ll just source them. Just make the pscale you instance them on quite small and i think they should just inflate to the rest length after they’re instanced.
You could stitch together those newly created meshes by creating dynamic constraints inside dops as well.

[@denitsabaycheva2311]

@@TimvanHelsdingen Thank you very much for your quick reply - I appreciate it

[@Wes_CREAM]

Great tutorial, learned so much!! I am trying to let that surface get a UV to export to an alembic so it is more versatile with textures but no luck so far, any help would be awesome - thanks :)

[@TimvanHelsdingen]

If you setup uv's on the grid before you deform it then it should be on there during the sim as well.
Alternatively you could freezeframe the first frame of your sim, unwrap that and copy the uv attribute to the simulated geo. Since the pointcount doesn't change that should also work.
Let me know if it works!

[@Wes_CREAM]

@@TimvanHelsdingen Yep that's what I did in the end and works, it just seem like a cheating way of doing it which won't hold up with more complex things - thanks for the help!!

[@TimvanHelsdingen]

@@Wes_CREAM Don't see why it wouldn't hold up? This is how I put UV's on FX stuff in production all the time. Would depend on situation if it'll be better to do uv's pre or post-sim though.

[@holoiresearch3438]

Hi Tim I am not sure what i am doing wrong. When I had @restlength *=3; in the expression @16:47, my vellum works just like yours. But when I had
float n = @Cd.x;
if (n > 0) @restlength *= 2;
float r = @restlengthorig*2;
if (@restlength > r) @restlength = r;
My vellum is not moving at all 0.0

[@TimvanHelsdingen]

are you promoting your attributes correctly? If you're working with point color on primitives you need to promote first, or load then with a point () function in the wrangle.

[@holoiresearch3438]

@@TimvanHelsdingen Solved it! Thank you Tim! I went back to the color part and it turns out I used a different red instead of the 1,0,0 red. Amazing!

[@kristoffermoth5408]

@@TimvanHelsdingen Hi, I'm running into the same problem, tried to look if the colors but they are the same as your tutorial - if i use a wrangle with the @restlength *=3; command it works perfectly, but as soon as i try to use the colors (just as Holoi) nothing happens. are there any other immediate caveats in this system maybe ?

[@kristoffermoth5408]

Apparently in 18.5.499, the vellum pressure constraint doesn't work with this method ( at least not for me) the strut softbody does thou

[@mihaiwilson]

Can you please turn up the intro music?

[@philippaps44]

thanks for the tutorial! what if the voronoi pattern changed over time?

[@TimvanHelsdingen]

you can pin points to internal animation to have them move with that

[@philippaps44]

@@TimvanHelsdingen yes i tried the "Match Animation" option under pin points but that seems to mess up the geo. its tricky because the blobs i have before siming are growing and shrinking, some dissapear alltogether, i guess its a bit confusing for vellum

[@TimvanHelsdingen]

@@philippaps44 well of course you cannot use changing topology in your vellum sim. What you probably want to do is generate a static highres mesh first like shown in the tutorial, then take the same voronoi input pattern and animate that (with noise or whatever) then point deform your highres geo by that animation and then plug that animation into vellum.
Also you probably need to create some additional stuff in the sop solver to make sure attributes grow over the geo instead of instantly transferring, else they'll inflate and deflate.

[@philippaps44]

@@TimvanHelsdingen tricky! thanks

[@GraphicBOMB]

saved my ass!

[@uzaykisi1863]

I've done exactly every step and still inflating all of them what am i missing?

[@TimvanHelsdingen]

you sure the attribute you’re putting on the primitives is a primitive attribute and not a point attribute? that seems to be the most common mistake for people who have this issue

[@uzaykisi1863]

@@TimvanHelsdingen yes, exactly both in Sop solver and the one before constraits null are primitive att, pls advise

[@janacker9262]

Can you do it a bit SLOWER so that people can really follow the tutorial???? Damn! Especially when you setup the color attributes...

[@dnch]

you can pause it or play it at lower speed