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I use Blender 4.2 and it worked very well in my Macbook M2. In the Blender system tab Apple M2 Max (38 cores) selected.

The problem started when I tried to follow a grass tutorial https://youtu.be/wQm3Baipva4?si=pqWUUHjQUeECNLFy&t=278 and I arrived the "Seperate and Loose parts" step (4:38), my Belnder file started lagging so hard it become unusable for work and I don't understand why because the statistic say there is not as much vertices: 421.127

I tried another file where I consciously started to upgrade the vertices and I reached 40,331,560 what is much more than the lagged project file and my machine worked so smooth and so well.

So I don't understand what the problem, because the test vertices was totally okay, but I couldn't follow the tutorial because of my machine, but my machine is strong it shouldn't be a problem at all because there is 64 Gb and 2Tb of storage, so no data justifies this result.

A.) Tutorial Lower vertices but lagging: https://drive.google.com/file/d/1sIHwfxFnY-QOkeq6eZ-n6KBChn2459yX/view?usp=sharing

Tutorial Vertices_ lower but lagging

B.) Suzanne test higher vertices _ but everythig is smooth: https://drive.google.com/file/d/1n0CwXaxsEazN__1EUd0wRMKnVkkWTggt/view?usp=sharing

This picture shows the higher amount of the vertices but works everything well

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  • $\begingroup$ What exactly do the statistics show if you use the "Realize Instances" node after the "Instance on Points" node? This value is usually decisive, because in the end all parts of the geometry still have to be displayed and rendered. $\endgroup$
    – quellenform ♦
    Commented Sep 4 at 22:39
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    $\begingroup$ There's a hell lot of variables affecting performance... Since you have a very high subdivision levels setting, it's probably the cause. Perhaps in one case you use instancing and in other not, or in one case you use GPU subdivision and in another CPU (because e.g. geonodes modify the data afterwards). This would mean that the bottleneck is sending the data to the GPU. Yes, the faster case has more vertices, but it needed to send less vertices to the GPU, and GPU internally created more vertices. $\endgroup$
    – Markus von Broady
    Commented Sep 4 at 23:22

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First, you are currently instancing meshes of 400K vertices on every distributed points of your Plane so it is not just 400k. Those are not counted in the statistics because instancing does not duplicate the data. But this must not be the direct cause of the lag because the orange outline is ! (Because Blender has to somewhat realize the instances to generate it or something similar). So if you deactivate the overlays you should see a the lag decrease.

Secondly, if like in the tutorial, you want to instance only one grass blade per distributed point. So you need to enable 'Separate Children' and 'Pick Instance'. Which respectively decompose your collection into one instance per grass blade and chose one of them for each point randomly.

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