Questions about normal baking via explosion
polycounter lvl 14
(I use mostly 3ds Max)
I'm not sure how to word this but I have several struggles remaining about baking complex objects. I've learned many things this year about baking normals. Check your smoothing groups and uvs, make sure normals aren't reversed, take out the high-poly render setup (shellac material and colored background), have the two meshed lined up close, have the high poly well beveled, and definitely don't bake the whole thing in one piece unless it's simple enough to do so. What I still struggle with is how to handle the explosion when it isn't a perfect example of ease (in other words the whole thing is made up of floaters and separate pieces). At some point there will be polys up against each other that need special attention.
1) How do you handle separating pieces of the mesh that are connected? I've asked over time about whether to model the low poly in one piece or in separate pieces. While I've never received this answer, in my experience it seems pointless to model it together because of this issue.
2) how do you go about returning after you have blown it up? You might be lucky and bake it easy in one shot but I've never done so. There is always something that need fixed, something that needs remodeled, retopoed, reUVed, etc. Then you have a destroyed mesh, with a different vert count, different UV layout, as per question #1 above, may even be shattered within each piece. You can't just throw it on the original pre-explosion mesh.
3) I still deal with symmetry seams. It seems strange to me that I can't search the forums and find a consistent answer to the problem. Is there a way in 3ds Max to do the smoothing groups by edges like in Maya? I read rumors of hard edges on the seam helping.
Any input from Polycount is appreciated as always. :poly105:
I'm not sure how to word this but I have several struggles remaining about baking complex objects. I've learned many things this year about baking normals. Check your smoothing groups and uvs, make sure normals aren't reversed, take out the high-poly render setup (shellac material and colored background), have the two meshed lined up close, have the high poly well beveled, and definitely don't bake the whole thing in one piece unless it's simple enough to do so. What I still struggle with is how to handle the explosion when it isn't a perfect example of ease (in other words the whole thing is made up of floaters and separate pieces). At some point there will be polys up against each other that need special attention.
1) How do you handle separating pieces of the mesh that are connected? I've asked over time about whether to model the low poly in one piece or in separate pieces. While I've never received this answer, in my experience it seems pointless to model it together because of this issue.
2) how do you go about returning after you have blown it up? You might be lucky and bake it easy in one shot but I've never done so. There is always something that need fixed, something that needs remodeled, retopoed, reUVed, etc. Then you have a destroyed mesh, with a different vert count, different UV layout, as per question #1 above, may even be shattered within each piece. You can't just throw it on the original pre-explosion mesh.
3) I still deal with symmetry seams. It seems strange to me that I can't search the forums and find a consistent answer to the problem. Is there a way in 3ds Max to do the smoothing groups by edges like in Maya? I read rumors of hard edges on the seam helping.
Any input from Polycount is appreciated as always. :poly105:
Replies
this is a good thread about this http://www.polycount.com/forum/showthread.php?t=117017
2. Very easy. You can set up a very simple key animation of all your meshes going into exploded state so you can then just use the animation slider to get it all back in the original state if you need so. I think you just need to press Auto Key and move parts (3ds max)
3. If you get symmetry seams it means you don't have your low poly symmetrical when you bake. You should: take your low poly you want symmetrical, delete half, unwrap, apply symmetry, move overlapped islands, bake that. Also, if you want to use Hard Edges you have to have uv splits where you have a hard edge, otherwise you'll get nasty black seams. You can plan your uvs accordingly to where you need your hard edges and then just apply Smoothing Groups by UV in TexTools plugin.
read more about hard edges here http://www.polycount.com/forum/showthread.php?t=107196
Anyway, if you can, check this out http://3dmotive.com/series/normal-maps-tips-amp-tricks.html
There are so many questions I could ask here. Here's what I am dealing with:
I have pieces right up against pieces and its modeled as one mesh. I'm astounded by that EQ post you linked (Impressed that he can bake that in one piece without tons of errors due to the cage). I'll chew on this for a while and post again later.
Thanks. That makes a lot of sense.
That's what I thought I was doing.
I'm with you on the smoothing, UVs issues. Actually another issue I have is too many islands because of smoothing. I don't understand how to have fewer islands and still have hard edges. So much of the advice you read is context sensitive.
Edit: also the seams are gone ... for some reason. The animation thing only worked so much though. I'm guessing you need to have it as one object first then move elements? I realized the hard way that you need the objects attached to bake, attached them, then realized I couldn't go back to the unexploded state so I have to use to separate files again. It did help me a lot with fixing the mesh and uvs together, then exporting the new mesh intact.
Having it as few lowpoly pieces makes it a lot easier to deal with.
As for what you posted above, what exactly is the problem?
We need to see it with the normal map applied.
It's a standard error, its just that I feel I can fix the others with time, but this one puzzles me as to what to do with the mesh to fix it. I have geo parts of the same mesh very close up against each other so the cage will push into itself as the model is now.
On another note, is there a way in 3ds max to keep my cage but add/remove geo? I'm guessing that wouldn't make sense since I would be changing the cage as I added/removed verts. I've worked this cage quite a bit and feel I need to change geo to move forward on a few areas. Should i at that point collapse, fix geo, the start saving another map and simply Photoshop them together? One of my goals here is to avoid painting any errors out like I did A LOT of last time I made this gun a few months ago. Layering two bakes just so I don't have to redo cage work should be OK right? Thanks! This is my second time with this gun and its been quite the struggle to bake it both times but I'm learning :poly142:
http://www.polycount.com/forum/showthread.php?t=81154
When it comes to the cage, you should not have to tweak it manually just push it out.
Layering bakes is not necessary either.
For that problem area, unless that part of the gun will be seen up close, simplify the lowpoly don't need that lip there.
Not sure what to say about the links to the stickies. Naturally they may be screaming the solution at me without me seeing it, but I don't think so. I can assure you that I've looked over them and the Wiki page to exhaustion. It's so much easier to evaluate simple cylinders and such. I tried getting rid of the "lip" but then whats left? Does it make sense to have a low poly over an empty space in the high? AS for the cage, yes I've given that comment myself to others on Polycount that it's not necessary to use the cage, but it is there and I've used it quite a bit today for hours. If you will allow me a moment, I can't fathom the hours lost to these bake attempts at this point. I guess the next step is to collapse and keep at it.
Edit: I think another issue I'm having is I'm scared to change the mesh geo because I know then that the original gun mesh sitting in Marmoset is then outdated. I was hoping the animation method would fix this, but it looks like I botched that up by not having it all attached at first before moving it.
Baking is a difficult thing to grasp, takes a lot of trying and failing.
You can modify the highpoly to make life easier, like that lip bring the highpoly closer so there is no lip there.
You could take a part of the gun trying to perfect that first.
Also I am by far a expert as this, which is partly why I linked the sticky.
Correct ... not sure why this comment. Either way, I'm giving up on explosion as this struggle is getting ridiculous. Tomorrow I'm going to try via layer sets similar to Xioliul's method in his Eat3d bulldozer video. This way I can have the elements separated without worrying about returning an explosion. This is how I used to do it anyway.
Thanks
Or you can save yourself trouble and just use bake by material IDs, then you won't need to explode anything. Look it up.
This sort of shape will always be a pain in the ass when baking. You should simplify this and merge the grip area into the rear area without that indent in the lowpoly, which will likely not be visible in game anyway.
Try to think of the lowpoly as a shell for the highpoly, you don't have to re-create every shape of the high exactly.
Setting up an exploded bake is really easy, just set keyframes for both the high and low poly chunks so you can easily split them apart and bring them back. Baking multiple objects and combining has basically the same drawbacks as explode baking (you have to split the meshes) but the added negative in that you have to do a bunch of different bakes and then comp them together instead of doing it all in one go.
@EQ: Thanks for commenting. I'll take that as "don't give up, figure it out". Am I right that you explode on sub-object levels because you need the LP as one object to bake? I'm eye-balling the two pieces together in the explosion. The 3d motive gun video on Youtube has him easily grabbing the LP and HP pieces together but then has to attach the LP before baking.
I did fix the issue by simplifying. I knew I would have to remodel, was simply drawing a blank so thanks for the input:
I'm sure I'll be post back later...
Yes, because max doesn't allow you to use multiple lowpoly meshes, you'll have to set up the keyframes in sub-object mode. It helps to move the objects numerically with easy to remember units like 1, 2 or 5 so you can come back with the highpoly and make the same adjustments.
Yep, looks much better, you can probably get rid of that redundant loop in the corner too now.
Here's one of the issues I've run into again. After setting everything up (the numerical movement idea worked well) I began tweaking the mesh on the explosion frame, scrubbed back to the beginning to see this? How do you work the mesh without this happening?? It happens whether I add the cuts in or out of autokey.
Thanks
Edit: I'm thinking that any edits to existing geo is fine, but if I create geo, it has no keyframe because I just made it. Having said that, I don't know what to do to fix the issue. Should I manually place the new geo back in place after I'm done baking or is there a better way around this? Or are artist simply not adding geo when they bake. I want to be as best as I can be. However, unless I can figure this out soon, I simply don't have a choice but to use a method I know. I'm all open for ideas as always.
I don't know what "baking animation" means. The reason the pieces are together in the LP is because you need that to bake the normal map in 3ds Max like EQ mentioned above. As soon as you attach them, you lose the animation. I'm not sure what you are suggesting I do...*shrug*
What I would suggest doing is test bakes without exploding to sort out everything else, like uvs, smoothing groups, projection errors, etc, and then when you're getting a clean bake, set up an exploded bake to get around overlapping issues.
How?
Dropbox, Google Drive, Speedy Share, FileSmelt etc. The list goes on.
http://speedy.sh/sFhKR/PBRBAKE-numerical.max
Note: it was, at least in part, a proximity issue with that last pic.
Edit: if you do get the file, see if the back section's UV shatter for you when you move it x=+25 ... they do for me. I've had that has happened to me a lot. When I move pieces around the UV brakes. That combined with the inability to add edges make me question this method. These things make the animation idea seem unnecessary, for me at least. What I tried to change will only brake things up if I try to go back to the first frame. Maybe I just don't get it enough, but if I use layers instead of explosion, then I can continue to add geo, change UVs, not have my uvs randomly break., etc. Perhaps others are just so much more experienced at modeling for bakes that they don't need the flexibility that I do? I don't know, I just know I want to get this done like nobody's business. :poly122:
Thanks.
You have all these indents in your low poly geometry, but do you think that maybe it's unnecessary? However you look at it, they are very small and don't affect the silhouette at all. I suggest you to try and just bake them down, it will be less troublesome for you that way.
Take it with a grain of salt, I'm no baking expert, see for yourself...
Also, It seems to me that your bakes lack Antialiasing. Try to crank it up next time, it helps with problematic spots.
After a grueling entire week of slaving on this ... the normal was baked clean in one fell swoop. I had done a clean bake on other projects before OK, but this gun was a nightmare ... definitely a study case in normal baking. In the end I did use 5 layers to bake and I needed them. Even after I had tested a lot with the gun in one piece and thought I had altered the geo enough that the only remaining issues were spacing ... I was quite wrong. My conclusion is that explosion only works for those who are either painting out the errors (which was my goal here to not do) or if you are already good enough at this that you are sure you are done altering the mesh/UVs (of course this opinion excludes any software I haven't used). I ahd to experiment every time it looked bad.
I accomplished the goals of the bake and learning about explosion and other baking techniques. I have been learning normal maps for over 6.5 years now, with the majority of the success being through this year. It's been the thorn in my side this whole time of moving from hi res to game art. I really can't thank enough for the help.
Note: I did end up taking that divet out of the LP ... most of the other ones were adding on over time because of bad bakes where the HP divet only looked good from a strange angle.