Intro to Mesh Economy

I know we all want to make "good" and "performent" and "fast" meshes. But right now you need to learn to walk, not run.

So at least for now, please be primarily focused on making art in general, practising, and getting your hours up. Artists have a habbit of getting hung up on and nitpicking minutia about performence, instead of making good art.

With that being said, I would like to introduce to you the concept of mesh economy.

Note - Before proceeding, recall back to our Lowpoly and Highpoly chapter. Your highpolys that you create have no requirement to be rendered in game, that's the job of the lowpoly! So in general, everything you're about to read, only applies to the lowpoly, not the highpoly.

Mesh Economy

Rendering anything takes time. Computers are close to magic, but not all powerful.

In general, the following is true - that we should always aim to use as little resources as possible to create something. Put another way - we should endeavour to allocate the resources that we do use, effectively.

Mesh economy therefore is this concept that the resources you utilize in your models should be well utilized.

For example, take the following 512 tri model:

This is an example of poor mesh economy.

See the disparity between how dense the rings are, vs the large silhouette defining edges? The triangles that this model utilizes, are allocated poorly to realizing its overall design.

The following mesh is also 512 triangles:

It is less detailed around the cylinder, however the overall curves and bends have a much more effective allocation of triangles. Again, the two meshes have the same triangle count.

This also isn't simply a matter of "making the polygons more uniform".

Take for example this shape:

This is a cube with one side beveled with 128 edges. this is far too much to depict this level of curvature. This mesh can be said to have poor mesh economy.

Take this 32 edged bevel however:

While this is objectively less detailed, we can see that the sense of curvature is still sufficient from this viewing distance, the model really doesn't need any more than 32 edges to depict this curve.

Lets keep this trend going. This is a cube, with a bevel of only two segments:

This cube can also be considered to have poor mesh economy. Why? The goal of this edit was to create a curve across the cube edge, but this detail doesn't utilize enough triangles to realistically depict that edge. So in this case, we actually would desire to consume MORE resources, not less.

The key point, is to utilize what we need, effectively.

Siluhette defining polygons

In general, your rule should be this: "If your triangle doesn't do something, get rid of it."

This most often manifests in terms of details which are silluhette defining or not. Take for example this common case of poor mesh economy:

We can see that the artist only added the loop cuts to enable the extrusions of a few square details. These additional edges, should be removed - as they still cost resources to render!

This is that same mesh, but with perfect mesh economy:

This mesh uses the exact number of triangles required to depict its shape, no more, no less.

Triangle utilization, vs Triangle Count

The key insight is this: don't worry about your polycount, or triangle count yet.

Worry about utilizing each and every single triangle that you put on your model effectively.

If you do this, it will be almost naturally impossible for you to make an inefficient model, and you in general will always have your meshes take up a triangle count which is optimal.

It's not just about the triangles.

There are other (more impactful) performance metrics beyond triangle counts. I will not teach you them yet. Focus only on making good work, studying, and utilizing your triangles effectively.

And again, this generally only applies only to your lowpolys.

✨Homework✨

I want you to take this blender file, and improve the mesh economy of all of its objects.

Note - Keep in mind, this concept primarily applies to our lowpolys, not our highpolys.