Why is it not possible to delete P with attribute delete?

[bobbybob]

I ran in to this problem, because I have a sphere, and I need a deformed version of it, but only as a rest attribute. I know how to do this in other ways, but I thought, that to just make the deformation, create the rest, delete the P attribute and then merge it with the original sphere would be nice. But when trying to delete the P attribute with a Attribute Delete, nothing happens?

Is this because P is a special attribute or something? Would be interesting to know.

[konstantin magnus]

Plugin both versions in an attribwrangle. Then you can take over the rest attribute from the second input with:

v@P = @opinput1_rest;

Morphing between both positions would be:

v@P = lerp(@P, @opinput1_rest, chf('morph') );

Point positions cannot be deleted, but you can set them all to zero:

v@P = vector(0);

 

[bobbybob]

Thanks for the answer @konstantin magnus, but what I really wanna know is, why we can't delete the @P attribute. Just to understand the data architecture better.

[Skybar]

Just guessing here but isn't that kinda the same as just deleting the point, since a point cant exist without a position? 

[animatrix]

P is a special attribute, and Houdini makes a lot of assumptions about the existence of P. If you are concerned about the memory use, just set it to 0 and it shouldn't take as much space.

[Iskander]

12 hours ago, pusat said:

P is a special attribute, and Houdini makes a lot of assumptions about the existence of P. If you are concerned about the memory use, just set it to 0 and it shouldn't take as much space.

Fundamental, I would say. :)

[LaidlawFX]

Since Houdini is a 3-D program the fundamental assumption is that all geometry data is associated with a point. A program that would be agnostic to this type of data would be excel.