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Full Version: Beginner Question. Why so many different types of vops?
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Andi Farhall

having run through two different tutorials that that both stick particles to a surface using vops, one does it in dopnet and the other in a Sop network. I tried to swap the particular vex processes but ran aground.

Inside the vopnet with some of it's ICE style familiarity i can see what goes on but I realise I'm actually lost regarding the multiple types of vops and how they work in different places like a sopnet or a dopnet.


Why so many different vops? why not just one if it's just driving vex under the hood? What's the difference between an attribute vop a point vop or a pop vop for example?

Why are some vops available in some places but not others? Why can i not have an attribute vop inside a dop network?

Last question, why does a vop laid down in a sop net have 4 inputs but one laid down in a dopnet only have one?

Plenty of doco/tutorial stuff for specific task but not much for overall joined up-ness.



N.B I added the hip file with both tutorial setups just in case.
Olaf Finkbeiner
Hi Andi,
i dont have an easy answer for you.

I also think this can be quite confusing.
And i think a lot is changing(has changed) with regards to this.
read here: []

As you see at the bottom of this page:
sop context:
Obsolete. Define a custom SOP operator with a program that edits geometry point attributes.

So some of the stuff is legacy…
see: []

“pops” are now part of “dops” (n H16)

in H15: []
this was not yet the case.

hope this helps a bit.

And: I only started learning Houdini 4 years ago. And it was so frustrating:
- i read about vex compilation and other stuff
- and when i found out about vex wrangles i was sooo happy.

Andi Farhall
Cheers Olaf,

it's a steep climb for sure but the view will be worth it.

Hi Andi

I'm just a beginner myself, but I'll try to share my insight.

in SOPs, a Point/Primitive/Vertex VOP is just an Attribute VOP with the Run Over parameter already adjusted for the type you want to change. it's just a shortcut.

other than that VOPs are going to behave a little different depending on the context, like if you put down a Volume VOP you gonna get density attribute to work with out of the box.

in DOPs I'm not too sure what the differences are, but from their name - Geometry VOP, Gas Field VOP, POP VOP, VOP Force - you can have an idea, and all of these work on the Dynamics Context, so considering the previous frame, simulation time, relationships, etc

I agree it's a bit confusing.

I am a learner, I'm quite confused about what is the difference between vopnet and attribute vop .
I have gone through different pages and I got to know about different attribute vop but I am unable to understand what is the basic difference between vopnet and vop

Shubham Rai
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