Is VEX geometry creation multi-threaded?

[magneto]

Hi,

Is there any info as to how Houdini creates geometry in VEX? I read somewhere that geometry creation is a post process that happens after the VEX code is ran.

Is this true? Also does Houdini do this operation in parallel?

Thanks

[kgoossens]

It's parallel with batches of certain size of points (I don't know how big they have to be). So if you are going to generate geometry using attribute wrangle in detail mode, then no matter how complex your geometry is going to be, it will be serial.

[magneto]

Thanks kgoossens, that was also my assumption about the Detail mode. I am not sure about the other cases though. Where did you get the information it's parallel though?

The detail mode is interesting but I also found that there was no way to set the attributes on these new points in the same Wrangle SOP. Did you perhaps do anything on that area?

[kgoossens]

This was being discussed on the Beta forum. When using points, prims it depends on how much points it has to handle.

use setpointattrib(),setprimattrib() etc...

[magneto]

Thanks kgoossens, I didn't know about those function.

Lastly do you also maybe know variable creation in AttribWrangle? In PoinyWrangle, I could use addvariablename, but I didn't see an alternative for CVEX.

Thanks again

[kgoossens]

just do @variablname. f@variablename to create a float variable. v@variablename to create a vector.

[magneto]

Thanks kgoossens, but when I do that, I only get the attribute not the varmap (Cd -> CD) variable. Is that supposed to be created automatically?

[dennis.albus]

For the variable you need to use the addvariablename function.

void addvariablename(string aname, string vname)
[/CODE]

VEX executes on elements in pages of 1024. So everything below that won't be multithreaded.

I think this is only true for editing existing geometry and not for creating new geometry.

Edited November 11, 2013 by dennis.weil

[kgoossens]

Hi Dennis,

This is indeed what you need to do in Vex but it doesn't seem to work in AttributeWrangle...

[dennis.albus]

I think this is due to the fact that it is only available in sop vex, but the attributewrangle uses cvex.