Turning a pretty big model usable

JasoB

I have a pretty big model here, with over 100,000 vertices and 200,000 faces, that i'm trying to make usable for Unreal Engine. About 5000~7000 would be ideal, however, i'm not sure which technique i should use to reduce the model, so that's why i'm asking here.

I already tried doing it by hand, but i underestimated the work involved and it would take a very long time. After that i started researching about retopology, since automated polygon reducing tools would clearly not help. After a few dollars spent on video tutorials and ebooks, i still can't understand how retopology works, and no matter what, my attempts to create a low-poly version of my high-poly model, through retopology, always fail.

I tried the TopoGun demo, as well the 3D Coat demo. Both software look good, but none of their retopology approaches actually helped me out. I also tried zBrush, but it looks awfully complicated and i haven't got started at all, even with all the high-quality tuts from Digital Tutors and others.

So, people, i'm here asking for help. A pretty desperate guy.

MoP

Are you able to post a screenshot of the model you want to make a lowpoly version of? It might help people give advice on what techniques to use.

I always used to do it by hand but retopology tools are really the way forward these days. Mainly they work better for organic models or character models, for environment stuff I still find it faster to do it by hand if necessary in most cases.

danshewan

I was faced with a similar problem with my St. Paul's Cathedral project recently. The original mesh was terribly messy, I hadn't originally planned it to be a game asset, and it was over 170k triangles.

I ended up remodeling most of the model, using the original as a template. I just finished the low-poly mesh, and I ended up reducing it to around 30k triangles. MoP's right - maybe post some screens of the model, and give us a little more information?

JasoB

Here's a small screenshot: http://img97.imageshack.us/img97/5429/modelscreen.jpg

The model is pretty good, and not messed up. Just big and too detailed. Do you guys know any good tutorials for retopologizing with 3D Coat or TopoGun? I really don't want to spend a lot on software that i won't be able to use, and my trial will end in some weeks. The videos in their websites are just showcasing features, they don't teach how to use them.

JasoB

I found some videos by Gnomonology about topology, but it's still pretty advanced. Do you guys know any other good tutorials?

ScoobyDoofus

Jasob: I think its important to understand what topology means in the context of a real-time game asset (especially a character) before one can really get a grasp on how to retopologize a relatively heavy asset like the one you're talking about. ( although 200k isn't really that heavy)

What matters is how well you are able to represent the volumes and outline of your character and still remaining in your triangle budget (you said 5-7k) while simultaneously ensuring that you have enough density in the limbs or moving parts anyway, to deform correctly when animated.

Please, post a shot of your whole model, with multiple angles. I'll draw up some stuff for you to help if you'd like.

Piflik

You could try to rebuild lower SubD levels in ZBrush. This should give you a headstart for reducing it by hand. I gues you could devide the Polycount by 16 that way (if it works). Or you can ask your Source, if you can get the model without the SubDs...

achillesian

if you dont want to do this manually, which is by far the best solution (unfortunately) then the "decimation master" plugin for zbrush is your next best bet, it works great. Although typically used on organic modelling, so i can't be sure if it would also work well for hard surface.

The one possible problem i see is it reducing high density areas equally with low density areas, to remedy this, exporting areas of the model with similar density would be ideal, thus focusing more on the areas with excessively inefficient polygons.

great example of Decimation master in use

[ame]http://www.youtube.com/watch?v=VCwcimDPZIk[/ame]

Reverenddevil

Use polyboost, the tools it has are pretty straightforward. You just need to understand how to retopologize and it will come to you.

MoP

Yep the model you show in your screenshot looks like a perfect candidate for retopology tools.

In fact, it looks like a lower-poly "control" model that's been smoothed and subdivided, am I right? If that's the case, I'd use your "control" mesh before subdividing as a starting point for the lowpoly. This is how I usually do it for character models and it saves a lot of time.

If not, then definitely learn how to use retopology tools (3d coat, zbrush, topogun, or any plugins for Max & Maya), it will serve you well in the long run. Don't give up just because you don't understand them immediately.
It looks like you're using Blender, does it have any sort of retopology tools or plugins?

JasoB

Thank you all for the attention. I'm using Cinema 4D, and unfortunately, there are no retopology tools that i know of.

Using Decimation Master and other automated tools really don't help. Decimation Master did not decimate the model at all, i don't know why. MeshLab and other reduction techniques screwed up the model, as i expected. I really can't think of anything else rather than retopologizing the mesh. I'm currently googling and getting all the info i can about, so i can do the job well. I do have a little rush on getting the model done, but it's more important for me to be able to do the process myself, and learn, rather than get things done.

binopittan

i don't quite understand which part of your model that makes you desperate ;p

retopology process is basically building your low poly model over your hi poly. i,m not familiar with c4d. but, do c4d have snap to vertex function on it? if yes.. then c4d can be used for retopology.

+1 to what ScoobyDoofus said. please post multiple shot of your model here so.. ScoobyDoofus can help you understand the process ;p

btw do you own a copy of zbrush?

CheeseOnToast

Decimation Master is not the right tool for making a lowpoly, game usable asset anyway. It's function is purely to reduce the polycount of your model to something that other apps can handle, with no respect to polygon flow etc. In other words, it'll make a much lighter model with a horrible mesh.