Hey there,

I'm trying to build an outdoor scene where I would scatter tens of thousands (maybe hundreds of thousands?) of grass objects over my landscape. Here's where I ran into trouble:

I'm using the instance node set to fast point instancing and am setting `shop_materialpath`, that points to a single material with heavy textures, as a point attribute. When I scatter 100 points inside of the instance node it shoots up to 28 gigs of RAM when I render it in Mantra. When I do 200 it shoots up to 45 gigs. I'm assuming it loads a copy of the material for every instance into RAM and I don't need that. I simply want to have the same material on each instance.

Just the mesh without the material applied works like a charm. I can easily instance 100k bushels of grass without Mantra breaking a sweat.

I looked a little bit into Delayed Load Procedurals and IFDs, but I only have an Indie License, so that's apparently out of the question for me.

So the question is, how do I go about instancing a lot of objects with textured materials?

Cheers,
Philipp

Is the RAM usage any different if you simply apply the material to the grass clump at the object level, then instance that, instead of using s@shop_materialpath?

Also, consider pre-converting your textures to .RAT and see if that helps?

Thanks for replying toadstorm!

There's no difference at all if I apply the material at the object level vs. shop_materialpath. They were already converted to .RAT by the Megascans plugin apparently.

Edit:

Just found out, that if I disable the displacement map it goes down to a couple of GB of RAM and when I additionally disable the opacity map it goes down even more. Can anybody explain why that is? Especially the displacement scenario?

I think clumps of grass are fine without displacement, but what if I had to instance a bunch of objects with their displacement maps attached?

I was just about to ask about displacement before I saw your edit!

You can try enabling displacement sharing on the object… the Mantra property is vm_sharedisplace. Without this, every instance will be diced separately which will understandably eat all your RAM.

I see! That means he will keep a high poly instance of every object in memory?
How do I use `vm_sharedisplace`? I didn't find anything on the object and the Mantra node.

On the Instance object itself, edit the spare parameters for the node and look for Mantra properties on the left. Search for the one called “vm_sharedisplace” and add it, then enable it in the Parameters window.

Oh wow, I had no idea you could set render params like that.

It works like a charm and stays well below 10 gig of RAM now. Thanks a ton!