Houdini Vellum - Pressure and attributes

Hello Everyone,
This is a simple tutorial on how to control vellum constraints using animated attributes
To download the file click on the link given below
www.rohandalvi.net/pressure
Black Friday sale - 26th Nov - 3rd Dec 2020
www.rohandalvi.net/
Link to patreon
/ rohandalvicreates

[@Erpty05]

Absolutely love this tutorial. By far the simplest example of using an animated attribute for a vellum constraint!! Can't find this anywhere else on the internet! Cheers mate!!

[@MBSJQ]

Awesome tutorials as always thank you

[@massimobaita7178]

Thank You very much, Rohan!

[@resilientpicture]

Thank you Rohan, Super useful.

[@Kmankeg]

Great stuff! thank you

[@FaddyVFX]

Wow, thank you, very informative

[@StephaneSOUBIRAN]

Thank you

[@harshadtemgire1297]

thank you bro

[@milad_savar]

nice very useful

[@cirakcemal]

Thanks Rohan. Renderman hair tutor please :)

[@STROBdotNET]

Hi Rohan thanks for this tut again! Where do you get the type from? For example if I want to animate te break threshold of a Pin to Target constraint will the type be "pin to target" (is this the constraint type but with a minuscule instead of majuscule? and do we need undesrscore or else? How do we know how to write the type exactly as needed?
and thanks for the file on your website, this is soooo useful with Houdini!

[@rohandalvi]

I was looking at the vellum masterclass on sidefx. They mentioned it in there. I don't know where you can find the rest. Houdini is a big mystery. 😄

[@monirul3d]

❤❤❤

[@almossawi]

I like to call you Guru Dalvi .. love your tutorials!

[@arbikerimov]

Hi, Rohan. Great tutorial. I wanted to ask you, what keyboard are you using ?

[@rohandalvi]

It's a Corsair mechanical keyboard. It's really loud :)

[@ibraheemyousef8114]

Thank you for providing useful information and lessons
But !!
I have a request, please complete the explanation as seen in the introduction. Lighting and materials did not complete
In order to fully understand the information and make use of the tech used
Warm greetings

[@shubhthesingh]

How to control the stiffness dropoff? by using paint/art directed way?

[@amirhosseinbaradaran2694]

Hi Mr Dalvi
I did do this method to animate the stretch stiffness and bend stiffness ,but it didn't work .
actually i have an attribute for each of them and I want to animate them in the solver(i created the attributes by paint node)
Could you help me please?
thank you.

[@genetixa]

Very Nice!!, however this setup looks like it doesn't scale well with denser mesh...

[@ShawarmaBaby]

Do you know why is it that I have to pump the Rest Length Scale up to 5600 to inflate my spheres and you only have to do it to 300? Also I am using Houdini 17.5

[@DovahDiaz]

Felt a deja vu 🤔

[@DenisVFX2]

Hello! Thank you for a great tutorial. I just tried to find a way to control rest length scale by point attribute in geometry. Thank you for solution.
But I have a little bit another quaestion: is it possible to make vellum cloth/hair simulation to follow some animation? for example I create a two geometries with animation and they starts intersects during the animation, and I want a vellum solver compute it, and solve intersections and also add some dynamics...

[@rohandalvi]

th-cam.com/video/uuct_19996U/w-d-xo.html

[@DenisVFX2]

@@rohandalvi Thank you! You are the best!

[@runelisether6256]

Thanks for the tuts. Learning something all the time :)
I only wonder of one thing. Why did you use "copy to point" sop to transfer "amount" attr. Why not use "AttributeTransfer " sop. I am just a newbie, but I recon that's the way to do it.

[@lgab]

There's no geo to transfer from, the attr transfer node uses distance in space to transfer and is mostly useful with non-identical geo, In this case the attribute lives on the spawn points which aren't necessarily similar to the spheres, so by copying again he will create identical geo which inherit the amount attribute robustly. Another option is attribute copy which uses ptnum to copy instead of spatial proximity, but again, there's nothing to copy from really.

[@mickeysage2515]

Reading directly from points works (H17.5) *point(2, "amount", @ptnum)*, if connect noise to the first copytopoints and set input 3 to first context geometry. Is there a reason for splitting into two copytopoints?

[@rohandalvi]

Just for organising. But you can do it in one node tree as well.

[@ArgoBeats]

Hi Rohan, this is great, but you couldn't just animate the Rest Length parameter in the Vellum Pressure node directly? Would that work the same?

[@smb3d]

This is an old question, but in case anyone else is wondering, no that wont work because the pressure constraints node and other constraints only read the geometry on the first frame. You need to use the vellum constraint property inside the solver to constantly update the attributes.

[@fallsins772]

Hi Rohan, thanks a lot for the tutorial, one question, how did you stopped the noise animation?

[@rohandalvi]

multiply with a mask.

[@fallsins772]

@@rohandalvi are you multiply scale of attribute by 0? this is the same as bbox in attribute delete?

[@rohandalvi]

@@fallsins772 use a mask by geometry. Animate that to get an animated mask if you want to modify the noise from a direction. And then in a wrangle just do
@amount = @noise*@mask;

[@fallsins772]

@@rohandalvi thought exactly the same, but thanks!)

[@vivincentable]

Hello, I have a question, I'm emitting a sphere from a vellum source, but I would like to give a random color to each sphere that is streamed, I'm trying to find to add an ID, but i can't find any in the vellum object, do you know how to solve this?

[@rohandalvi]

Just give random colors to the points and when you use copy to points the spheres will automatically pick up the random colors from the points

[@vivincentable]

@@rohandalvi I'm not using a copy to point, I'm using one sphere emitted in continuous mode in the vellum source, and that's why I can't figure how to attribute a different color for each emitted sphere

[@chlnapanda]

Can't really see your mouse cursor.

[@christophershaju3737]

camera tracking and impliment effects with houdini and finial out , Tutorial Please

[@rohandalvi]

I haven't done camera tracking in over 10 years. I barely do any compositing either. So I can't promise a tutorial in camera tracking. Sorry.

[@christophershaju3737]

@@rohandalvi 😖😖😖😖🙏🙏👍

[@robbie_]

"the reason it's not working", this is the entire story of Houdini. An expert can use it. A novice will give up after about five years of trying :p.

[@Al1987ac]

It's kinda true for all software.)

[@MsAnkush12345]

Tutorial is good, but you should at least tell the reasons behind what u r doing, right now it is like just following along, no reasoning.