I'm trying to work out some particle axis stuff.

I'm curious about the particle gnomon that is displayed in the viewport, as I can't seem to get any access to it. I've attached a picture of this. I see the velocity represents the z axis.

But how do I get the up vector? Or the the left/right bit for that matter (is there a fancy name for this one?)

cheers,
-j

The Y (green bit) is the up vector. But are you using the up Vector in POP to adjust the up vector?

I am not using the up POP.

I'm a bit confused by this whole thing. How do I access the value of that green bit? If it was a normal, I could say add normal on a Point SOP and the value would be there. But if I add up in the Point SOP, it's just 0,0,0 …?

thanks!
-j

bump

Hi,

If you have an up vector prior to the popnet, it will get transformed.

Now I just noticed the polyframe sop which seems new in 9.5, which will compute an orthogonal frame (with the proper options checked), you can use that before your popnet.

Now this seems a bit convoluted, and I thought the up vector pop node was supposed to add a proper up vector, but it's not.

So I'm curious about an easier way as well

The Up Vector POP allows you to *add* an up vector, by giving it expressions or values on the parameter. It doesn't know which up vector you want.

If you have an up vector prior to the popnet, it will get transformed.

brilliant!

And this polyframe sop seems quite powerful, hmmmm…