3D Week 03 – Optimizing Crates
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Hi! This week we have been working on our 3D-crates and how to optimize the models for game usage. First of we have learnt that a 3D-model or mesh should only contain polygons with a maximum of four sides otherwise they won’t be handled well and the mesh might end up distorted and not looking like your original model. Any polygon with a number of sides greater than 4 is called an N-gon (I guess the N stands for any number, like in mathematical formulas, might not be correct though). When 3D-modeling for games you might also want to consider the amount of polygons you put in to your model. A higher amount of polygons results in a higher “resolution” on your model but drains a lot more performance than simpler 3D-meshes. So depending on what your model or mesh is going to be used for and how close to it the player is going to get you want to consider the amount of polygons. A good rule for cutting down on the poly count is that anything that doesn’t break the silhouette of the mesh can probably be removed from the mesh. Examples for what doesn’t break the silhouette would be small details and parts of the mesh that is negative extruded into the mesh. This information is added in a later stadium using something called normal-maps or bump-maps. My Sci-Fi crate was optimized and corrected by Simon Brundin.
The problem with my Sci-Fi crate was that there were some N-gons (marked red on the top two screenshots) in it, so they have to be fixed as they had more than four edges. Another thing that isn’t as critical as the N-gons but can be improved is the poly count. By reconnecting and arranging the vertexes in the spheres he did some savings on the poly count without braking too much of the shape. I guess as the spheres isn’t actually breaking the silhouette at al they might can be reduced even more, you might also have to make sure that the appearance of the holes is corrected by using a normal map in a later phase. In this case I’m pretty satisfied with the poly count, so next time I would’ve just make sure that there aren’t any N-gons in my model. Next model is my medieval crate, and is worked on by Rickard Folland.
The problem with the medieval crate was the same as for the Sci-Fi crate, which was the amount of N-gons (marked red in the two top screen shoots). The high amount of n-gons I get probably founding in that when creating my crates I use a tool called Pro-Boolean ( it can be found under compound objects and is different algorithms for how to objects shall interact with each other where they intersect). I use Pro-Boolean to easier and faster doing my model. By performing a Pro-Boolean the vertexes doesn’t connect to each other just the planes and that often results in polygons having a high amount of sides. By the using of Pro-Boolean the poly count raises significant as you have to fix all N-gons as well. Rickard didn’t finished working on this crate as there where so many faces to fix and he did spend most of the time working on making the topology better as that was something the Pro-Boolean did mess up as well. My last, the cartoon crate I fixed myself.
The problem with this crate was the N-gons (again lol). This crate is way simpler than the others in one way as all lines are straight (no smooth or rounded surfaces or shapes) so this mesh can keep a very low poly count without messing with the silhouette at all. So what I did on this was basically making all faces to four or three sided polygons tops by connecting the vertexes needed or removing the unnecessary ones that occurred when I used the Pro-Boolean tool. Next time I think I’m going to skip the Pro-Boolean tool for some of the steps as it gave me much more work in the clean-up phase, which takes a lot of times. The reason why I tempt to use the tool is that I have done some 3D-modelling for 3D-printing. And when you 3D print the poly count is something you rather keep high than low, and your models need to be fully watertight. For 3D models you only use in digital form (for games and such) you want the poly count to be low and if it saves on your polys the model don’t have to be watertight. So next time I probably will use another method were I can. That’s half for this week.I’m also going to post about the prop I picked at Gotland Museum for the modelling-assignment in school. CYA -Lui  |
