Forums Technical Discussion Jitter points on surface... How?

Jitter points on surface... How?

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Masoud
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Hi Guys;

In my simple test scene, I converted a geometry(sphere) to points, then I add a “Point Jitter” sop to it.
The “Point Jitter” , moves points randomly along local axis of geometry, but I want to move them along NORMAL of each point.

I don't want to use Scatter, because I want the points exactly on geometry's points.

Any idea?
Edited by Masoud - April 27, 2017 04:58:30

Attachments:
JitterPoints.jpg (260.9 KB)

Masoud Saadatmand (MSDVFX)
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Enivob
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Jitter along normal is just displace, right?

There is Displace Along Normal that you can construct inside a VOP.
Or just throw down a mountain SOP.
Edited by Enivob - April 27, 2017 08:34:53

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Untitled-1.jpg (200.6 KB)

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Konstantin Magnus
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int seed        = chi('seed');
vector shift    = rand(@ptnum + seed);
int prims_nb[]  = pointprims(0, @ptnum);
float prims_num = 1 / float( len(prims_nb) );
int prim_choose = int( floor(shift.z / prims_num) );
int prim        = prims_nb[prim_choose];
vector pos      = primuv(0, "P", prim, shift);
@t = prims_num;
@P = pos;

pointprims tells you what primitives are connected to each point. with prims_num, prims_choose and prim the third component of a random value named shift gets assigned to one of those primitives. the first and second components of shift determine the UV location on the chosen primitive. Change the seed to get variations.

If you want it less overlapping, just set prim_choose to 0 and maybe delete prims_num.
Edited by Konstantin Magnus - April 28, 2017 03:33:42

Attachments:
jitter_on_surface.jpg (27.3 KB)
jitter_on_geo.hipnc (61.3 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
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Masoud
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Enivob
Jitter along normal is just displace, right?

There is Displace Along Normal that you can construct inside a VOP.
Or just throw down a mountain SOP.

Hi Enivob and thanks for reply;

I don't want points leave the surface, so Displace or Mountain doesn't works.
Masoud Saadatmand (MSDVFX)
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Masoud
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Konstantin Magnus
int seed        = chi('seed');
vector shift    = rand(@ptnum + seed);
int prims_nb[]  = pointprims(0, @ptnum);
float prims_num = 1 / float( len(prims_nb) );
int prim_choose = int( floor(shift.z / prims_num) );
int prim        = prims_nb[prim_choose];
vector pos      = primuv(0, "P", prim, shift);
@t = prims_num;
@P = pos;

pointprims tells you what…
Hi Konstantin Magnus;

This is want I need, Thank you.
Edited by Masoud - April 28, 2017 06:27:49
Masoud Saadatmand (MSDVFX)
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edward
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I haven't but I thought the Mountain SOP already did this?
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