Retopology for game models

evermotion · May 2013

Hello I'm quite new here and a noob at game models. I'm more a general media modeller.
I wonder if game models need a totally different approach to retopology, uvmapping, texturing. I have sculpted an organic ship and this will be for a low poly mobile game. I need to retopologize this model and not sure if the cylinders should be a separate mesh or it has to be one piece with the main body. If this was for video or stills I would just separate it. For games I have no idea about the logic yet if this will be ok in game engines. Any advice appreciated.

Heres the ship

Eric Chadwick · May 2013

Depends if you are going to use normal maps or not. Normal mapping works better with good topology, to avoid seams. See this thread: Understanding averaged normals and ray projection/Who put waviness in my normal map?

Also if the model is going to be deformed, like an animated character with smoothly-bending limbs, then you need good edge loops in the topology, to support that bending. See: http://wiki.polycount.com/CategoryTopology
http://wiki.polycount.com/ReTopologyModeling

But in your case, if you're not using animated-deformation on the model, you could simply use an automated decimation tool, like Meshlab.
http://wiki.polycount.com/CategoryTools#Decimation_Software
It will make what is often called "triangle soup", as in no edge-loops, just a sea of triangles when you look at the wireframe. But this is often good enough, and a big time-saver.

evermotion · May 2013

Thanks for the tips. I didn't know its ok to autoretopo game assets. This ship will not deform so I guess I should try that.
I manually retopoed and uv'd one of the ships. After reading some forum posts, wikis and tuts I created the retopo like this and uvmapped along edges I want to be hard.
I wonder if mirrored uv's are ok for game engines?
I will paint this with 3dcoat and also do the normal maps there.

bacteria · May 2013

Mirrored UV's are fine, but I would mirror only wings and leave middle section as one piece. Another thing is that your topology seems to be dense if this one is for mobile devices

evermotion · May 2013

Thanks. Whats the logic of leaving the middle section as one piece? I'm just starting so any tips on that would help.
I thought it was very low already. Less than 1k polys.

bacteria · May 2013

if you mirror in the middle it may be very noticeable that texture was mirrored , any scratches or dirt will look like roshak test. I rather make it unique for left nad right side. Of course it's not a rule. Other thing is that sometimes you may get bad looking seam in the middle, depending on map you bake or shader you use in engine.

Retopology for game models

Replies