Static mesh size versus performance

[Hellclown]

How big does a mesh have to be to warrent it having a large poly count? for instance, if I have a mesh that's the size of a barn, but has 9000 polys is that reasonable? Assume that all the polies are quads and the overall model is relativly simple, the poly count is due simply to size and amount of detail required by the size. I.E. the large chunks of sedimentary rock along road sides and the like particularly on mountain roads where the path was cut out of the mountain side.

[taz1004]

It's not the size but complexity of the mesh that determines reasonable polygon size. A box size of a barn should only have 12 polys. And how close you get to the object. All mesh should have lowest polygons at acceptable visual quality. You have to be the judge of what is acceptable.

Sedimentary rock should be done with normal and height map. Do not model all the details.

[kaleden]

12 polygons for a barn? What is this, 1998? While I agree that 12 polygons would make for a good low LOD version of the model, developers aren't limited to texture maps when it comes to quality graphics.

I think the real question is not the mesh complexity of a single object, but rather, of the complexity of the whole scene. 9k faces is good for a single character, so it shouldn't be bad for a prop like a barn. It really just depends on what else is going on.

[myleslambert]

Yeah kaleden is right,
In the unreal engine I prefer to not constrain myself to polycounts too much, then again, don't go silly, just add the required ammount of detail to keep things looking good. For example a few extra tri's to add some planks to the side of the barn would be fine.
With the unreal engine in mind, think more about texture and material usage rather than polygons, those are going to be what is hitting your performance.
For example, what really makes 'great' game art these days, is squeezing the entire barn texture into a single 2048 or smaller by using clever overlapping textures and decals.

[taz1004]

12 polygons for a barn? What is this, 1998? While I agree that 12 polygons would make for a good low LOD version of the model, developers aren't limited to texture maps when it comes to quality graphics.

I said a BOX size of a barn. It doesn't matter its 1998 or 2050, a box should still only have 12 polygons. And he didn't say a barn specifically. He said a MESH size of a barn.

[Hellclown]

I don't know why everyone latched onto the barn comparison. I asked because I want to make a set of macro detail meshes. I guess the way I wanted to ask my question would be: If I have a large mesh is there a point where the number of polies negitivly effects the performance due to the mesh's larg vilibilty?

[CorvaenOboros]

large meshes deserve more tris , they occlude objects behind them and thus increase performance.

polycount is really not an issue anymore, better to focus on texture res , shader complexity , and overlapping translucency , those all generally cost more performance.

for a large cliff face like in the image i think is totally reasonable to have 9k+ tris.
and if possible tiled textures would help performance , so as to be able to use and reuse lower res textures on similar meshes like for a set of different cliff meshes.

as far as a limit the point at which it is negatively affected , seems to be around 40-60k tris, which starts to bug out on import, welding verts or deleting verts.

[taz1004]

I don't know why everyone latched onto the barn comparison. I asked because I want to make a set of macro detail meshes. I guess the way I wanted to ask my question would be: If I have a large mesh is there a point where the number of polies negitivly effects the performance due to the mesh's larg vilibilty?

Well, I thought you were only using the barn as size reference. Unless you're going into hundreds of thousands, you really shouldn't concern yourself with polygon count. But it's always good practice to use least acceptable amount of polygons.