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[SOLVED]Scatter Points Don't Stay Constant?

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Posted (edited)
I have a fairly simple scene. The goal is to create points above a planet surface so I can instance clouds to them. This means the sphere is very large.
 
I have projected a grid upon the sphere using a Ray node and I scatter points on the grid. I then copy a 2 point line to the grid and delete the first point of the line. This way I can use the length of the line to lift the points off the sphere and into the sky.I animate the grid so that as it translates it conforms to the sphere.

This setup works well, however, the scatter inherits some jitter in the points for some reason. The random seed for the scatter is a constant so the same points should be generated every frame. This is not happening, instead the points are mostly the same but then occasionally jump then jump back to where they are supposed to be.
 
Does anyone know how to keep scatter points constant?

 

scatter_point_jumping.hiplc

Edited by Atom

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Posted (edited)

Attribute interpolate plus in the scatter sourceprim and sourceprimuv needs to be on.

Here is fix version.

scatter_point_jumping_FIX.hiplc

Edited by Sepu

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Thank you, that works.

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1 hour ago, Atom said:

 This way I can use the length of the line to lift the points off the sphere and into the sky

in ray, there's Lift, isn't this what it's for ? (-50 will lift it 50 above hitpoint)

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Posted (edited)

Yeah, but I don't think Ray lift will accept a per-point attribute i.e. f@rnd_length? By using the line, I can stamp a random length for each point in the line to make some clouds higher or lower than others.

Edited by Atom

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9 hours ago, Atom said:

Yeah, but I don't think Ray lift will accept a per-point attribute i.e. f@rnd_length? By using the line, I can stamp a random length for each point in the line to make some clouds higher or lower than others.

ahhh...but where there's a will there's a way....so simply randomize pt colours...then in ray Lift put in something like -10*@Cd.r

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Yep, you are right, that would work too.

untitled-1.thumb.jpg.12a256c199992c67421ffb067e727046.jpg

It would be nice if all parameters, on all nodes, could be driven by attributes. It seemed like the last time I tried that with a node the node did not support attribute driving and I wasted my time trying to set that up. Now that we have special shapes for nodes perhaps a node should be displayed in a certain shape if it's values could be driven by attributes?

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