Low poly hard surface modelling - Floaters
I'm working on a low poly building but I'm not sure how to approach some of the details. Hopefully this will be going in my portfolio so I was just wondering whether employers mind or even pick up on floating geometry?
The floaters save polys and create a much cleaner mesh, but are there any technical reasons not to use them? Is it viewed as cutting corners?
Cheers in advance
The floaters save polys and create a much cleaner mesh, but are there any technical reasons not to use them? Is it viewed as cutting corners?
Cheers in advance
Replies
That aside i see no real problems using floating geometry(until someone proves the opposite xD)
You're usually going to want to weld your verts if you're using engine-baked vertex lighting (older Unreal work for example, and probably the mobile stuff) or when you are animating the mesh, where skinning differences make animated floating parts slide against each other.
It's also a good idea not to push the verts of the floater inside of the main structure, this can cause other lighting issues, especially if the engine is using vertex lighting. If the verts are in a dark spot (like inside the mesh) you get dark shadows blending to the next vert. SO instead of placing the verts inside you want to float them just above the surface. The objects pivot point plays a huge roll in this so it helps to keep to a grid.
Of course a lot of the "do I float?" question is very engine/game specific stuff which is why its hard to find a definitive answer. In general its fine to float, but know your game and how it handles things, if you're not sure test it out, if your tests are inconclusive ask someone on your programing staff. That level of communication is what places are looking for when they put in job postings "communicates effectively", its not just HR bs hahaha.
TL;DR:
-Welded is good for creating clean lightmaps
when an engine renders a model it does it in multiple passes in a heirarchy:
the object, the materials, the smoothing groups, the uv coords and for each time when those split apart. say you have an object with 8 faces, 2 materials used on 4 faces each, 2 faces share a smoothing group, and each face has it's own uv position - for each time you go down that sub-level the engien is creating more patches, or individual islands it has to render, so in our example we would have to render 8 patches, 1 for each face - regardless of whether the polies are stitched or if 4 polies share a material.
so from a performance point of view it can be important that you model to reduce the amount of these issues you run into. a single smoothing group, uv's connected as much as possible, 1 material per object etc; all these things can help but it's actually quite impossible to work when you try and limit yourself to making a "perfect" model, almost impossible due to the nature of 3d and the way we currently work.
other factors are engien specific, as the previous poster noted, unreal liked welded meshes because it makes your lightmaps cleaner.
other engies use vertex-based lighting and you will get bleeding and bright spots if you don't make certain verts welded.
other engines that have special systems require completely connected meshes to perform things such as breakability.
so it is a very relative subject, there is no one perfect way to do it. but it helps to udnerstand that large uv clusters, as few materials as possible on a single object, and as much connected as possible will help you create a mesh that will perform well in an engine.
at this stage we are not really worrying about polygon counts we have LODs to help performance if needed, and LODs to help stream content if we are running low on memory, so the only thing floaters will help you with is speed and convenience when modeling.
and from that point of view i would say: use floaters. don't do unneccesary work if you don't need to. make sure you don't have huge intersections and that you delete backfaces amd you will be alright.
tl;dr:
connected is more technically beneficial
floating and intersected is more convenient
the cost trade-off is probably very little in 95% of models, so do whatever is easiest and quickest.
Sticking to floating meshes and merging everything together on 0.01% will save more polies.
However; I do see many people using welded apprach as well. So I'd go for whatever suits you best.