Author Topic: Corona Scatter Objects at the Edge Causing Blinking  (Read 1109 times)

2021-01-31, 10:42:45

Byteman3D

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I'm rendering a cell membrane like the one in the image. I'm using Corona Scatter, thanks to the creators of this renderer, Scatter is highly efficient and reliable.
You might guess my scatter objects --the blue balls with legs on them-- I also added animated noise to the scatter surface so that my cell membrane looks alive, always in slight motion. Enabled Temporal Consistency so that scattered copies move with the surface, but right at the edge of my scatter surface, some of the scattered objects disappear and re appear (Due to the noise movement for certain) Not only appear and disappear but as one disappears others appear due to the empty space - or so I think.

I must add one more detail, that my scene size might be causing trouble. This was a tiny portion of a very large eye object. The eye extents were about 240000 centimeters, and the tiniest atom object in the cell was 0.02 cms. This size difference is way large for 3dsmax to handle together. My tiny objects were indeed shaking during a straight motion.

That is why I have seperated the scenes. Brought the cell portion closer to the origin and deleted even the camera motion other than  the 50 frame close up and zoom out sequences, and the cell animation in between those.

I haven't rescaled the cell as the shaking movement of the straight moving objects are no longer noticable. Precision problem seems to be solved but this scatter problem.

Is is common for scatter objects to come and go arbitrarily at surface edges with noise modifier, or is this still related to the scene scale? As I look at the scattered copies far from the edges , I see not even a single one disappear. This is about the edge.
What do you recommend?

Edit 3: Limiting the noise to only to Z axis does not help. 



Any ideas?

« Last Edit: 2021-01-31, 12:05:29 by Byteman3D »

2021-01-31, 12:13:05
Reply #1

romullus

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You can try to assign noise controllers to Corona scatter's translation tracks in curve editor - this should solve dissapearing objects problem, since distribute-on object wouldn't need to be animated anymore.
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2021-01-31, 13:34:05
Reply #2

Byteman3D

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There is a Discrete Translation Track and a Translation To - From tracks. I couldn't figure out which one to assign the noise controller.

The first one didn't seem to have a noticable effect in the viewports and the latter one would presumably move each scattered unit back and forth, which is not what I want. I need sort of waving on the surface.

And let me ask a followup question:
I need these scattered objects just side by side but what I get is some of them have spaces between them while some are interpenetrating. Also it is not about the noise movement. I use the avoid collision setting but it just doesn't seem to help. Is it simply because the amount is not enough.
What parameter should I set to achieve surface fully covered with scatter objects but without colliding at a resting frame?

« Last Edit: 2021-01-31, 13:46:41 by Byteman3D »

2021-01-31, 14:22:20
Reply #3

romullus

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You should try pattern scattering options instead of random scattering - look for it in surface scattering rollout.

As for the controllers, i've looked at them on my pc and oddly it looks that they aren't named at all, all i can see, is the bunch of question marks. Is this the same for you?
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2021-01-31, 14:55:38
Reply #4

Byteman3D

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This is the scene and I seem to have no problem with tracks with a single exception that there are complete empty tracks.

When I see  meaningless characters around Max interface I remember malice scripts. Question marks may be about missing things though.

2021-01-31, 15:41:57
Reply #5

romullus

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That's interesting. What Corona version do you use? I found that transformation attributes in Corona scatter are made as point3 nodes, but i don't see any of those in your screenshot. I will report the issue in bug reporting board.

Did you try the grid options yet? Maybe it would solve dissapearing instances problem and you would not need controllers for that?
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2021-01-31, 16:16:53
Reply #6

Byteman3D

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Indeed grid selection solved the blinking problem :D Thank you. I still need to figure out how to apply a homogeneous UVW mapping to this cell object. It is like a box but with smooth edges with a large radius. I'm not very well with Unwrap UVW modifier.

Spherical didn't distribute well, box didn't distribute well.
I used a morpher modifier with a target obtained from the clone of the cell. Spherified it, assigned Spherical UVW Map. Then morphed the UV assigned spherical cell to the original cell. It worked. :D but so primitive.

This is Corona 6 with a student license running on 3dsmax 2021 update 3.

2021-01-31, 16:31:57
Reply #7

Byteman3D

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All Tracks didn't fit in 1080 pixel height this is the complete tracks for my scatter object.

None of the Scatter object tracks have controllers assigned by default but you can assign a point3 controller to any suitable track.

2021-01-31, 16:52:09
Reply #8

romullus

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Ah, now i see. I think you need to assig noise point3 controllers to translationFrom and translationTo tracks, but if grid distribution solved instances poping issue, then it's probably better to stick to noise modifier on distribute-on object, since it will give you better controls over the noise.
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