wagon wheel

Tamarin

Hi,

I am trying to reduce the number of polys on this wheel. It is currently 248. I would like it around 100 but without all the jagged edges. I'm not even happy with the profile of this wheel to be honest. If anyone is willing to share a trade secret I would really appreciate it.

Tamarin

Ohhhh, right! I get it now.

Xenobond

I can't come close to remembering how many polys each wheel was now (I can hardly remember what I did last year, let alone 4 years ago), but you can see that I used fewer segments on the inner track of the wheel that on the outside. I think I also used fewer segments from where the spokes meet at the hub, down to the ends as well.

If you're trying to get as low poly as you can, then you might want to try the solid wheel. Should save you plenty of polys to put into the outside shape of the wheel.

Eric Chadwick

An old trick is to use alpha planes for the profile. Could work for you. I'll try to dig up an example.

Ah OK, here it is, a 10.7 MB pdf:
http://www.ericchadwick.com/examples/tutorials/low_polygon_technique_for_next_generation_systems.pdf
Saved this awhile back, don't know where I got it from. Anyone know Jolyon Myers? No url in the pdf, only the author's name, and a web search doesn't reveal much. Oh well. Good tips though.

Steve Schulze

It depends how close you're going to get to it. We use the alpha plane technique for DS and PSP, but I think once you go any higher resolution than that, the trick would start becoming more obvious.

Tamarin

Thanks for all the help.
I don't want to change the wheel into a solid wheel because I have a reference image and I think it would change the look of the cart too much. I'm going for an early 20th century and the solid wheel looks more medieval or roman to me. I can understand how that would save polys.
I also don't want to go the alpha map because I'm not sure what that will do in the physics engine. I think collisions are mesh based. I want to try this some time.
I like the idea of reducing the mesh from the outside to the inside and I have been working on this. Currently I have a higher number of polys on the outside front and inside rear of the wheel. I have added more detail to the hub and higher number of spokes. I have also added to the number of polys which I was trying to reduce but I'm more pleased with the look of the wheel. I'm now at 264.
That is a very nice looking canon model.

Ghostscape

[ QUOTE ]
An old trick is to use alpha planes for the profile. Could work for you. I'll try to dig up an example.

Ah OK, here it is, a 10.7 MB pdf:
http://www.ericchadwick.com/examples/tutorials/low_polygon_technique_for_next_generation_systems.pdf
Saved this awhile back, don't know where I got it from. Anyone know Jolyon Myers? No url in the pdf, only the author's name, and a web search doesn't reveal much. Oh well. Good tips though.


[/ QUOTE ]
That was put out by the Cinema4D folks I believe, or possibly the XSI guys but I'm pretty sure it was the C4D guys.
edit: it was the XSI guys they talk about XSI in the whole article

Some of the idea in there are a little wacky and focus on shaving a few triangles at the expense of a lot of texture space, but it's pretty good overall and even if the techniques as described are a little goofy in the examples the concepts behind them are pretty solid.

Daz

So in danger of opening up a huge can of worms here, aren't a lot of those 1 bit alpha poly saving tricks a bit outdated in theory now eric? Curious to get your thoughts. Everything I read lately, and everything I'm told by our graphics engineers, is that the most efficient way of drawing models these days, is to interrupt tri stripping as little as possible. The more you swap shaders, the more draw calls you make, the bigger the performance hit. Usually you're better off actually drawing more tris than interrupting the rendering to render things in a *different* way. I feel like drawing all the spokes as uber low poly tris would be faster than drawing them as something funky like a normal and alpha mapped plane (and thus, a different shader from the wheel), but I would be curious to get more thoughts on this. Possibly one of those things that is engine dependent.

Tamarin: Really, Per hit the nail on the head. It makes sense where possible to choose forms/designs that are easier to describe with an economy of tris.

However, If in this case thats the wheel design you need, just think about bang for the buck. About how it will look in game. Personally for instance, I wouldn't even care if my spokes were 3 sided, or that the axle piece had no segments, If I could have more roundedness in the circumference of the wheel. At some point this becomes somewhat subjective I suppose. But yeah, bang for the buck in game, that's what this is all about.

Tamarin

I'm happy with the axle piece at 36 polygons and the spokes have 3 sided at the outside and 4 on the axle totaling another 84. 120 in total that would make the wheel 144. I'm going to set myself a new limit of 200 total, I think 100 was too cheap. Even though I'm happy with the center I'm going to hack it up and trade it to the outside. If I make the spokes flat I can knock them down to 24.
I appreciate this site.

Eric Chadwick

Good point DaZ, yup you're right. Outdated trick given how costly context switches are on today's hardware. I can pump more vertices out vs. swallowing the cost of using alpha-test, which generally looks shitty anyway. Can't antialias alpha-test unless you do some apparently costly tricks, with strong limits.

Maybe still useful on mobiles/handhelds though, where there's more limited vert power? Also maybe software rendering. Thankfully haven't had to deal with that.

Thanks for calling me to the mat.

Illusions

So using alpha planes for rounder wheels, sharper/smoother blades, etc. is out unless you really need it for something?

Tamarin

I didn't get down to 200 but 254. Its less than the original and I think a bit of an improvement. Thanks everyone for the advice.

The total model is 628.

Ben_Flex

Your Wagon is nice. Seems that you work with blender