Hi there,
I'm a new SunBurn Community edition owner (and I love it!!!) and this is my 1st post so hello SunBurn community! ;) Anyway I am just trying to get to grips with the workflow from zBrush to Max to Sunburn, but am totally lost as I can't find any documentation on the use of normal maps anywhere on this site, and for some reason my normal map doesn't show right in sunburn but is fine in max - odd?! Does anyone have any ideas why?
Its difficult to speculate as different software tends to expect textures/UV's to be formatted in different ways, but as I say I can't find a list of requirements specifically for SunBurn on the site so I presume there isn’t any? As such, I've just been trying everything, and none of it works basically – doh!
For a start, the normal and diffuse info has been created in zBrush, which generates the UV's upside down, so they need to be flipped for max to accept them, but then further, max also likes the Green Channel Y component of the normal map to be flipped as well.
Flipping the diffuse map works fine in SunBurn, but the normal doesn't look right flipped, and I just expected to do the same - so I'm at a bit of a loss and would mega appreciate any help if anyone out there has any ideas of how to resolve this?! Poor dragon…he's lost his bumps :(
I deconstructed the windmill example to examine the normal info of the maps within but it doesn't seem to have been changed - the channels aren't flipped or anything - so who knows - I'm not a normal map expert though - just a curious creative!
To help here is a couple of pictures of the issue in question:
[ MAX ]
[ SunBurn ]
One thing I was unsure about is that as an early test I used the Adaptive UV tile option in zBrush which creates UV info automatically by assigning each poly to a small square texture area, this is the reason why the UV's are broken down into tiles which shows as aweful random squares on the incorrect normal map.
I do intend to create proper UVs for the dragon in max as this is always better result wise - but in the 1st instance I just wanted to see that everything works before I spend the time unwrapping it! However I wondered if this might be the problem – so again if anyone has any ideas/theories I would really appreciate your help, anyway thanks in advance and will look forward to hearing from the community - SunBurn Rocks!!!
Kat ;)
Hi Kat,
SunBurn's built-in materials use the first uv channel for both the diffuse and normal map. This is so you don't have to duplicate the channel when the diffuse and normal maps use the same uv space. When using baked-down normal maps, make sure the diffuse uses the same channel / uv space and both will layer correctly.
Also make sure the normal map is in tangent space (it sounds like it already is, based on the green-channel issue with Z-Brush) - most apps will give you the option of object or tangent space.
Flipping the normal map green-channel for Max is probably because the texture generated by Z-Brush is upside-down - this affects the encoded normals and flipping the green-channel puts them back in tangent-space.
Let me know if this helps!
Follow me on Twitter – development and personal tweetsAwesome XNA Videos – Lighting, Rendering, and game videos
Hi John,
Congratulations on an awesome product ;) and thank you for getting back to me so fast! After reading through your reply I realised that becuase I'd used the quick export method out of zBrush (tool section: one with limited options) I was not able to correct the normal map suitably for export due to its coordinates being flipped. As such, I used a different method with more options (i.e. zMapper) which sorted the issue out and now my dragon is happy he has found his bumps!
Thank you for your help I really appreciate it ;) and I'm looking forward to having some fun with this technology!
Happy Kat
trax4katz:becuase I'd used the quick export method out of zBrush (tool section: one with limited options) I was not able to correct the normal map suitably for export due to its coordinates being flipped. As such, I used a different method with more options (i.e. zMapper) which sorted the issue out
Hmm, that's very good to know - I'll pass this along to Alex. I think we generally uv map low-res models (in the modeling app) before creating the high-res versions, so I'm not sure we've ever run into this situation, but we'll definitely watch out for it.
Thanks!
I'm sure Alex will be well clued up as to zMapper - You're absolutely right, the correct approach is to use an external app like max or maya et al, as they give you so much more control. I rather foolishly decided to use zBrush's quick fix because I was basically excited and just wanted to get something normal mapped into sunburn ASAP ;) the auto UV adaptive tile creator in zBrush is great in theory but does an awful job of unwrapping! As for the difference between simple normal map export and advanced (below) in zBrush there is a ferocious amount of options to confuse - so I tried the easy way out 1st - but all is good in the end, so I'm going concentrate on getting some decent UV's sorted out now in max! Anyway a big thanks for your help and communication - very much appreciated ;)
Kat
[SIMPLE]
[ADVANCED]