Nested instances in geometry nodes signficantly increase render memory useage #111459

New Issue

Jason Clarke · 2023-08-24T07:34:11+02:00

Jason Clarke commented

2023-08-24 07:34:11 +02:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 536.99

Blender Version
Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-08-22 23:13, hash: 6e20beba22df

Short description of error
If you have a geometry nodes system instancing an object/collection which itself contains instances, there will be a significant increase in memory to render the scene. This can be a significant issue with trees, as forests may contain many copies of a tree model with its own geometry nodes system making many leaves and branches.

Exact steps for others to reproduce the error

The attached scene contains a monkey with cubes scattered on it, then a plane which scatters said monkey across it.

Disable the geometry nodes modifier on the monkey (the one with the "cubic suzanne" system) and render. Note that Cycles memory usage is barely more than an empty scene, even with tens of thousands of instances of the monkey
Enable the "cubic suzanne" geometry nodes modifier. Note that there is now a significant memory cost for each additional instance for the cubic monkey. Only a few hundred instances are needed to add hundreds of MB of memory usage.

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 536.99 **Blender Version** Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-08-22 23:13, hash: `6e20beba22df` **Short description of error** If you have a geometry nodes system instancing an object/collection which itself contains instances, there will be a significant increase in memory to render the scene. This can be a significant issue with trees, as forests may contain many copies of a tree model with its own geometry nodes system making many leaves and branches. **Exact steps for others to reproduce the error** The attached scene contains a monkey with cubes scattered on it, then a plane which scatters said monkey across it. 1. Disable the geometry nodes modifier on the monkey (the one with the "cubic suzanne" system) and render. Note that Cycles memory usage is barely more than an empty scene, even with tens of thousands of instances of the monkey 2. Enable the "cubic suzanne" geometry nodes modifier. Note that there is now a significant memory cost for each additional instance for the cubic monkey. Only a few hundred instances are needed to add hundreds of MB of memory usage.

geonodes_instance_memory_bug.blend

937 KiB

Jason Clarke added the

labels 2023-08-24 07:34:12 +02:00

YimingWu commented

2023-08-24 09:22:39 +02:00

Looks like the same as #109731. Not really a bug, but it still could be faster.

The performance of the GN instancing is being improved, with task here: #92963.

Will close this as a duplicate. Thanks for reporting.

Looks like the same as #109731. Not really a bug, but it still could be faster. The performance of the GN instancing is being improved, with task here: #92963. Will close this as a duplicate. Thanks for reporting.

YimingWu closed this issue

2023-08-24 09:28:45 +02:00

Blender Bot added

and removed

labels 2023-08-24 09:28:47 +02:00

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