Should boundary meshes like walls and cliffs be planes or 3d objects?

camafe

I am modeling in Blender to use the meshes in UE5.

The walls and cliffs that bound the scene should be made with a plane with displacement (high poly baked into low poly) or should it be a 3d object? I am talking about meshes that we will only see from one face, we will not be able to go around them.

A plane would mean less polys than a 3d mesh, but also I fear there might be light bleed problems and tiling problems. Also, to change angles would be a problem. Plus the tiling pattern is quite noticable. I could deal with angles and the tiling pattern by introducing 3d meshes at the corners of the plane.

A 3d mesh would give variation to the cliff, since you can just rotate the mesh in any direction and create instances of it, so you could have a lot of variation with a few cliff meshes. But that is also more polys. 

Also, should textures be left procedural so that we can rotate the mesh and scale without loss of detail? Think about procedural masks like edge masks, pointiness, etc. that I would replicate in UE5.
The other option of course is to bake a material for each mesh in specific, that is more draw calls. But maybe with like 10 cliff meshes per scene I can already have enough variation, so 10 draw calls should not be a problem.

Thanks.

Eric Chadwick

It really depends on the art style, and how the player controls their camera. Lots of options depending on usecase. It sounds like you're aiming for a realistic art style, and you're planning for a first-person free-roaming game style? Some images would help, and maybe existing games you're inspired by.

camafe

Eric Chadwick said:

It really depends on the art style, and how the player controls their camera. Lots of options depending on usecase. It sounds like you're aiming for a realistic art style, and you're planning for a first-person free-roaming game style? Some images would help, and maybe existing games you're inspired by.

I imagined the game as a third-person, with the camera being close to the player, at his back except for cutscenes. The game takes place in a gigantic hollow meteorite, full of caves and canyons. These rocks I want to make are the walls of the caves and canyons. Think that maybe the boundaries of the meteorite (projected into a cube) would be 4km x 4km x 4km. 

I am aiming for a semi-stylized look. Difficult to explain, so here you have some reference images of characters:
https://www.artstation.com/artwork/v2vmVa
https://www.artstation.com/artwork/VJZL1R
https://cdna.artstation.com/p/assets/images/images/055/019/708/large/murs-render-base1.jpg?1665937759
https://www.artstation.com/artwork/OmPGWb
https://resizing.flixster.com/L6V0X-A12Hfhw9c4VL9KHfonpPU=/1100x618/v2/https://resizing.flixster.com/-XZAfHZM39UwaGJIFWKAE8fS0ak=/v3/t/assets/p17997860_e_h10_ac.jpg

As for hard surface modeling, I would try to create seomething that goes along with the style, some references of the environment:
https://www.artstation.com/artwork/b54oYg
https://www.artstation.com/artwork/yD1Zn5
https://us.v-cdn.net/5021068/uploads/editor/wy/ov7l6icny78r.jpg

Benjammin

Use 3D meshes of rocks and cliffs.
Unreal can handle the polys, and a double sided mesh is twice as versatile. 
Yes, you'll want to use triplanar mapping and detail normals. Its fine to have a baked mask map for each mesh - generating curvature within UE's materials can get expensive, and sometimes its cheaper to just throw a texture at it.

camafe

Benjammin said:

Use 3D meshes of rocks and cliffs.
Unreal can handle the polys, and a double sided mesh is twice as versatile. 
Yes, you'll want to use triplanar mapping and detail normals. Its fine to have a baked mask map for each mesh - generating curvature within UE's materials can get expensive, and sometimes its cheaper to just throw a texture at it.

Is triplanar necessary? I thought of creating smaller rocks, UV unwrapping them, bake the textures and finally in UE combine the rocks to create large cliffs. If the walls are the same mesh, then they use the same UVs and I could merge them or instance them.

poopipe

Triplanar mapping is fairly expensive but throwing a load of uniquely textured rocks around can also be fairly expensive. 

The answer to this is (as always) 'it depends, and you can't tell without profiling your specific situation' 

If you're in unreal just do what epic recommend - which is to stack up a load of meshes and HLOD them 
If that doesn't work out you'll need to fire up insights, identify what's actually upsetting it and change things accordingly . 

The benefit of working that way is that you aren't committing to things that are difficult to undo . 
Premature optimisation is often worse than not optimising because optimised things are - by their very nature - not malleable

Benjammin

camafe said:

Benjammin said:

Use 3D meshes of rocks and cliffs.
Unreal can handle the polys, and a double sided mesh is twice as versatile. 
Yes, you'll want to use triplanar mapping and detail normals. Its fine to have a baked mask map for each mesh - generating curvature within UE's materials can get expensive, and sometimes its cheaper to just throw a texture at it.

Is triplanar necessary? I thought of creating smaller rocks, UV unwrapping them, bake the textures and finally in UE combine the rocks to create large cliffs. If the walls are the same mesh, then they use the same UVs and I could merge them or instance them.

Its not necessary, but does let you scale your meshes for extra variation. 
By all means try out what you're thinking - the best result for your purposes might be a combination of approaches. In my experience, kitbashing rocks together into larger formations tend to look like rubble or manmade rock walls, but maybe that's a look you want.