[Idea] - Height Maps

posted on July 3rd, 2011, 3:54 pm

Here's an idea to help lower the poly resolution on some of the larger models.  Use height maps and apply them just like you would a texture.  The job of the height map would be to adjust the number of polygons on the model by how many pixels of the height map are on each pixel.  All that would be needed is a bare minimum poly-resolution model and the height map would do the rest.  I believe that's how FSX get's their terrain height and there's an Orbiter mod that does the same thing.

posted on July 3rd, 2011, 4:47 pm

So basically the heightmap would create more polys? So it would turn out just as high poly either way?

In most programs that use heightmaps, the polys are all already there. The heightmap just adjusts the height of the vertices.

We already have/use bump maps, which help a lot with keeping un-necessary polys down, but I don't see how a height-map can help any further.

Plus, any half-decent modeller can make a good model within a good poly count, so it's not a problem here.

posted on July 3rd, 2011, 5:56 pm

The model itself would be a very low-poly model.  The height map is just there to make the model more detailed the closer you get to it by physically creating new polygons based on distance and changing the positions of the new polygons.  The model itself would only have to be a few hundred polygons, but the heightmap would create up to thousands more polygons based on distance.  Plus, it really doesn't ease up the pressure on the modeler.  It does just the opposite, but in the long run, saves disk space and the detail level in the model is adjusted in a much smoother way.

Have you seen how some of the racing simulators adjust the resolution of the models?  It's a pretty noticeable transition that the heightmaps should be able to eliminate.

posted on July 3rd, 2011, 6:03 pm

Why not just use LODs? It's still low poly models becoming high poly ones as you get close to them, and it's already in the engine, no masses of coding required.

posted on July 3rd, 2011, 6:11 pm

Like Atlantis said, the Armada engine already has LOD functionality so long as people make LODs for their models. It does basically the same thing but doesn't require writing a new feature for the engine. Also, the height maps sound like they dynamically create polys rather than loading a different model, right? I can see that having a negative effect on frame rates for those of us with older computers.

posted on July 3rd, 2011, 6:23 pm

That's why this is NOT a request.  Because it will take a lot of coding to implement.  The result would be smaller files sizes for the models as a result of not having as many mesh groups for all of the detail levels and a lot smoother transition between resolutions.  The downside is in creating the heightmap on a per-model basis that will be harder than creating the textures.

It may or may not have a performance impact.  It probably depends on the model detail and the computer, but I imagine that it would be able to increase overall performance when you get say 20+ object on the screen at once.

PS:
Fleet Ops may not need this because their detail transitions are so smooth already.  In fact, their detail transitions are smoother than a lot of simulators are.

posted on July 3rd, 2011, 6:43 pm

it will have a significant performance impact. what you describe is a form of tessellation.

Its impractical to be used in games like armada, due to the giant CPU overhead to create the geometry. Yea I know, graphic cards could do that, but the gpu has enough to do with he large amount of textures Fleet Operations uses, and the CPU is stressed more than enough too.

posted on July 3rd, 2011, 8:28 pm

Good point.  This is probably best to use in only simulators.