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Is computing instances collision only single threaded?

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Is computing instances collision only single threaded?

Unread postby machieb » Fri May 14, 2021 10:45 pm

Hello,

I have the problem that when I use collision in scatterers it takes ages to compute it. In the progress view it is called: "Computing instances decimation based on pairs instances collision of: build:/...../scatterer."
In my project I have only a small lawn and the collision detection takes 76seconds every time I change something in the scatterer, like the probability of the geometries. I have only 5 plants in the scatterer.
Is that collision task not multithreaded? In the taskmanager only one core is working on that.
This is a really time consuming problem!

Cheers
Attachments
Decimation_scatterer2.jpg
My taskmanager
Decimation_scatterer.jpg
My progress view
machieb
 
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Re: Is computing instances collision only single threaded?

Unread postby adomon » Mon May 17, 2021 2:02 pm

Hello

Indeed, collision detection is not yet multi-threaded, but it's not normal at all it takes so much time with only 5 instances in the scatterer. Under one billion instances, the time it takes to compute collision detection should be reasonable.
Do you mean you have 5 plants but much more instances referencing these plants in the scatterer ? Could you please share with us your project ?

Thanks
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Re: Is computing instances collision only single threaded?

Unread postby machieb » Mon May 17, 2021 3:24 pm

Hello, thanks for your reply.

In the moment it is not possible to share a project in clarisse 5 because "Export Project Archive" is broken. I already send a bugreport about that which was veryfied.

In my project I lowered the point count of my point cloud from 10million to 1million.
Now "Computing instances decimation based on pairs instances collision of: build:/...../scatterer." is much much faster. It takes only a seconds to compute the collision.
When raising the point count of my point cloud again to 10million points, the collision task takes again >70seconds.
In my scene I was not close to 1billion instances as you mentioned.
I have only 5 plants in my scatterer (see attachment).

Are there plans to make the collision detection multithreaded?

Cheers
Attachments
Collision_detection_01.jpg
The settings of my scatterer
Collision_detection_02.jpg
The settings of the point cloud
Collision_detection_03.jpg
The 3D view
machieb
 
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Re: Is computing instances collision only single threaded?

Unread postby machieb » Mon May 17, 2021 3:36 pm

I created a simple scene in Clarisse 5 with boxes. The collision detection takes not as much time as in my lawn scene because the geometry is simpler, there is only one object in the scatterer, but you can see the effect.
Open the attached scene and raise the point count in the point cloud from 1million to 10million.
Then you see the calculation takes much much longer.
On my computer I have <1sec calculation with 1million points in the point cloud, with 10million points it is >24seconds.
Attachments
Clarisse_scatterer_collision_detection.project
The simple scene
(43.21 KiB) Downloaded 38 times
machieb
 
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