Exporting to Unity 2020.3.3f1 LTS

[Pocatella]

Hello all,

We've recently purchased a SpeedTree for Unity subscription only to find out there has been this importing issue which apparently has been going on for years: imported models are deformed due to the mesh polycount restriction (65k polygons). I've read in the previous thread that this should have been fixed with recent Unity versions but it doesn't seem to be the case as we are using Unity 2020.3.3f1 LTS. Now, we also have SpeedTree Cinema edition which we had for a year or so. My colleagues have already generated 300+ models using it for another purpose. Now we want these models in Unity as we're making some sort of a simulator thinking that the SpeedTree for Unity dynamic LOD feature would save us a lot of time instead of exporting High, Medium and Low resolution one by one from the Cinema edition and set it up in Unity. The wind simulation was a bonus as well.

As we're working on a simulator, we needed high resolution models. Our high resolution models are about 692k quads. The draft resolution is about 161k quads. I have tried doing optimization as stated in the docs but even doing them doesn't really do much like halving the accuracy for segments. It doesn't really decrease the polycount a lot. Very low accuracy makes our model very blocky which is not an option and the fact that it's a big time sink for us to do all of this for our 300+ models which we cannot afford to do. Our models have tons of branches and no leaves (see image below). The branches are the highlight of our model so we cannot remove them.

In the image below inside a Unity scene, the tree on the left is from the ST file and the one on the right is from an FBX file imported from the Cinema edition (which is what we want). The main difference we found is that in the Cinema edition, you can group meshes by hierarchy which actually decimated the whole tree into smaller meshes which makes sense and probably preferable anyway to avoid that 65k polycount restriction issue. In the Unity edition, it does not seem like we can do this when you export a model. You only have options to export LODs and billboards. How come? Is there any other workaround for this issue?

[Greg Croft]

Hello,

The bugfix for draw calls >65k has been submitted, but we are at the mercy of Unity when those roll out.

I do have to point out that Cinema export isn't really meant for realtime. The geometry won't be optimized and the textures won't be packed. It'll just be a very slow-drawing tree, and you'll have to set up the materials yourself, including packing the textures (or making a shader in shader graph). Not to mention the Cinema EULA prevents use in real-time scenarios. You'll want to look at SpeedTree Games, either Indie or Full. If you have already purchased Cinema for another reason, then shoot an email to [email protected] and perhaps we can work something out for all your use cases.

Unity will break up FBX files if they are too big, which is why that worked for you. It's not the hierarchy export specifically. Games Indie can export a game-optimized FBX that should come into Unity fine, albeit without wind effects (but it sounds like you're not worrying about those anyway). You can use the SpeedTree shader and disable wind in the materials, or pack the textures differently to use the regular HDRP Lit shader.