[BUG] Experimental - Placing foliage on Instanced Static Meshes with Procedural Foliage Spawner

Development Asset Creation
, , , ,
1

Using 4.81 version.
Tried Procedural Foliage Spawner in my project. It refuses to place any instances on Hierarchical Instanced Static Meshes. HISMs are populated in Constructor of an actor blueprint.
Switching HISM to regular Instanced Static Meshes helps but only partially. With a relatively uniform settings for foliage placement some of the ISMs are completely avoided.
All green meshes are exactly the same and placed using constructor script, all have a simple hexagonal collision mesh:

2

Hi ,

I just want to make sure I fully understand so I can accurately reproduce this on my end. You are saying that you spawn HISMCs with a blueprint construction script. After this you place a procedural foliage spawner in the level surrounding the HISMCs and press “resimulate”. At this point no foliage spawns on the HISMCs in the level?

Additionally, if you change the HISMCs to IMCs, the foliage will spawn on some instances but any that are uniformly scaled will not have foliage spawn on them after pressing “resimulate” in the foliage spawner?

3

Hi ,
First part regarding HISM is correct.
Second part is potentially an issue with collision of hexes. Now that you’ve mentioned it I suspect that I’m still scaling them by z axis only. Hexes are 25 meters tall and some of the second level hexes, which are 25 meters above the zero, return raycast at 15 meters while collision with physics objects still happens at 25 meters.
There was another issue with the distribution of foliage, I’m not sure if it’s visible on screenshot but it looks like foliage is not placed on the edges of the grid, like foliage was cut there. I’ll make a simple project which illustrates it.

4

This is a link to a sample project:
https://www.dropbox.com/s/pp5pb1ovu81oay5/ProcFoliageISM.?dl=0
There is place in constructor where ISM can be replace with HISM.

With uniform scale of hexes, Foliage does spawn on Instanced Static Meshes. For HISM no difference they don’t spawn.
Unnatural pattern in which foliage is placed (grid like) is probably a result of my settings for foliage.

5

Hi ,

I was able to reproduce this and have entered a bug report, UE-18175, to be assessed by the development staff.