ZBrushCentral

Retopology Questions

ZBrush Usage Questions
#1

Hi everyone,

I made a sword model a while back that a friend of mine would like me to make into a game model but I’ve got some questions and problems about doing it and could use some advice.
The model I have is ridiculously Hi-Poly, (probably more than was needed but i subdivided until it was as smooth as i was looking for, its not efficient poly use ) its broken into around 8 subtools and is 10+million polys.
I dont have the original base mesh anymore, the model has no UV’s and no real subdivisions (I used Dynamesh a lot).

  1. Can anyone recommend a good retopology method?
  2. Should i retopo each individual subtool one by one or do it as one whole mesh?
    3)What would be the best way to do the UV’s for this?
    4)The model has engraved text and such (which is why i pushed the polycount so high) whats the best way to retopo that sort of detailing?

Any help would be appreciated, I’ve been looking at different tutorials but im not able to get such a high poly model into Blender and so far my efforts to retopo in ZBrush have given some unsatisfying results. I’m sure im overlooking something in the way im doing it but im not sure what.

#2

I’d start by using a copy of the save file, and run Decimation Master on it. This should reduce the size of the file drastically, while preserving all the detail that you need. You may even want to make two copies: one that is decimated lightly so that it still has all the details (great for baking the maps from), and one that is decimated more heavily so it only has the overall form and silhouette of the model (which should be all you need to retopologize, and would make it much easier to bring into an external program like Blender should you wish to retopologize it there). If the engravings are small and don’t affect the silhouette, the normal map and other textures should be more than enough to create the illusion of them.

UV-wise it might depend on the engine, but some support different ratios so you might be able to get away with 1:2 or even 1:4

#3

If it’s being used for a game the question you need to answer is how close to the sword are you going to see?

The farther away the camera is from the object the lower the detail needs to be. Also since it’s a sword I’m guessing you won’t need to animate it in unusual ways (warping, bending, etc.) as it’s probably just always a solid object. This means you shouldn’t have to worry about good topology flow and you could just decimate it down to your required polygon count.

#4

Hi guys,
Thanks for the replies, I have managed to get decimation master to drop the count to a level that Blender will just about manage to handle it so im going to give the retopology a shot in Blender and see how that works out. I think its mainly because of the changes in surface shape can be quite quick and i just need to make sure i get the poly transitions looking good and definately more efficient than the high poly.
I think it’s going to be for something on Skyrim so it will need a 1st person mesh, a lot of the detail is from the guard area and back towards the grip so its not all going to be on screen a lot but i’ll probably still need to give it a fair bit of the polycount to look good. I’m thinking 4-5000 polys should be my limit on this.
MentalFrog the problem with really heavily decimating it is that the algorithm doesn’t differentiate between the different areas so pieces i can probably get away with representing with a dozen poly’s is given the same attention as an area I would give maybe 100.
I’ll see about getting some images up at some point it should make it easier to discuss… although obviously i run the very likely risk of looking a bit dim :slight_smile:

#5

It does if you mask off the areas accordingly. You can mask 100% the areas you don’t want points to change, mask 75% the areas you don’t want to change as much, etc… The decimation will still bring it down to your target number but will take the masking in consideration.

#6

Wow! thats pretty handy. I had no idea that you can change the poly density with decimation master using masking. Thanks for that MentalFrog. :smiley: