Merge Actor : Static Mesh VS ISM

Development Rendering
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1

Hello !

I’ve got a question regarding arctor mergings, we have multiple options, 3 :

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  1. What the benefit between merging actor as single mesh (first option) vs ism (second option) ? I understand what ism is, i would like to know in what scenario (eg) this is usefull ? I guess small amount of different mesh who is not used a lot amount a level (eg. bookshelf) vs a large amount of bullet of the ground is the main difference, but i would like to make it clear in my head.

  2. what is the second option ? i doesn’t really understand it.

  3. is is the pro/con of the 3 button ? 3 technique for optimisation ?

Thanks !

2

Option 1 combines the meshes into 1 static mesh and groups their materials.

Option 2 makes a single new mesh and material, which is supposed to look like what you had but is more efficient. It’s usually used to make ‘proxy’ meshes which look like a sort of low LOD of a complex mesh, at a distance.

Option 3 basically turns the meshes into foliage. They will be one ‘thing’ but multiple copies of meshes are replaced a single mesh and instances. It might be more efficient if you have a large number of the same mesh ( > 1000 ).

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3

thanks for the answer.

Using ISM for a lesser amount of mesh < 1000 have an impact ? like a con un performance ?

4

If you don’t have extreme numbers of meshes, instancing them won’t really have any effect.

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5

Thanks for the prec clock !

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6

Oh, another and last questions :
For ISM :

  • When ONE ism of the ism are in frustrum view, does it draw all the others ism ? or, he occlude ism ?
  • If we have a LOT of modular mesh, who is basically the same, is it worst to ISM them ? or it will break occlusion in some way ?
7

I think with that conversion it’s HISM. That means they are grouped and appear and disappear in groups. It is possibly to get problems with bunches of them flicking in and out of view.

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