Primitive Sop Problem...

[ddingddong]

Hi~

I like to make simple explosion effect.

my idea is a metaball is going around pillar and some debries fly away.

But, I faced with some problem when I using primitive SOP.

Top image is my pillar (looks like stone pillar huh?) and particles are attached each polygon faces.

Then, in primitive SOP, I turn on the 'Do Transformation' check box.

Now you can see what the problem is... every faces are twisted !

I don't know what the problem is...

Please help...

[sibarrick]

Its because you are using a template input. So every primitive is getting copied to the template, when you turn on do transform you are saying move all the primitives to the template. To get them to match the original you'll have to construct an up vector and normal so the orientation matches. This isn't really my area, but there must be an easy way to fix this situation.

[SpencerL]

Basically all you need to do is just above the first input of your Primitive SOP, add a Facet SOP and check the box "Post-Compute Normals". This gives you a normal (N) attrbute which determines the way the face is rotated. And if you want those prims to be able to separate from each other, which sounds like you do, then on the Facet SOP also chect the box "Unique Points".

[ddingddong]

Now I just check the reply.

Sibarrick and Spencert's explanation are very helpful to understand two inputs of primitive SOP.

When I construct nodes, I overlooked normals and keep looking under my nose.

Now I see what I missed it. Thank you~

The point is match the original to template. Right?

Have a nice day~

Thanks again.