Beginner Question. Why so many different types of vops?

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Hi,

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.

so…

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.


cheers,

Andi.

N.B I added the hip file with both tutorial setups just in case.

Attachments:
stickToMe-x2.hiplc (426.9 KB)

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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:
http://www.sidefx.com/docs/houdini/vex/contexts/_index [www.sidefx.com]

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:
http://www.sidefx.com/docs/houdini/vex/contexts/pop [www.sidefx.com]

“pops” are now part of “dops” (n H16)

in H15:
http://www.sidefx.com/docs/houdini15.0/vex/contexts/_index [www.sidefx.com]
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.


Olaf
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Cheers Olaf,

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


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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.
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