Tangent Normal map issues
polycounter lvl 13
I'm pretty sure this has been covered somewhere and if so shot me the link. Here is the problem my tangent space normal map looks like shit. How do I fix with without spending hours in photoshop. Should I just re-bake it?
Replies
2. Object normal map
3. tangent normal map
If you look below, the boxes on the far right have a similar issue to what you have, smoothing issues because the angle of the low poly's edges are too sharp yet are one smoothing group. (low-poly smoothing groups try to fake a smoothed surface with shading, when the angle gets farther away from perfectly flat, more and more shading errors will show up. )
Now if you harden the edges and bake, you'll need to split the uv's apart as explained by the second pic.
Examples of 90 degree edge baking:
Hard edge example:
And some general explanations of the whats and whys of normal maps and such:
http://www.polycount.com/forum/showthread.php?t=107196
Good luck!
Here is the update made for my normal map
Maya is synced with itself and while I agree that he should make an effort to simplify the the normal map, it is important that he understands why this is happening in the first place. Also, just to clear things up, the 90 degree rule is misleading. There is no specific angle at which you must split a model. It is more productive to think in terms of flat surfaces with complicated smoothing on them. That means looking at the topology of the flat areas and adjacent surfaces.
Looking at your scene file the normals on your objects were set to unweighted. Maya 2013 should be defaulting to "angle and area weighted". I don't do much baking inside maya so I don't know if maya 2013 always bakes with that expectation or if it uses whatever normals are selected in the drop down menu. Either way, it looks like that got switched.
If you send the normal map file over I can confirm that is the problem.
Earlier versions of maya didn't have this drop down and they used a different method internally (I think just angle weighted but I would need to check on that).
You have been a great help I will try and post an update later today!
That is a good quuestion I check in a new file to see is that is the case.
How do i go about fixing the issue? just adding more geo around the edges of the mesh? Here is the current geo!
But really, what you want to do is split any edge thats 90 degrees. You just don't want to do that it, it causes some serious issues with smoothing most of the time. So you have a choice, you can either split the UV islands much better, which would give the sides their own islands and then the flat top its own, which would help. Or you could add support chamfers all along the edges, which would help but also increase the polycount far too high.
In short, your best bet is to just re-think your support loops and look at where you actually need all those tris. If they don't add to the silhouette, get rid of them. Add a few more tris down near the teeth on the blade, not a lot, just a few more, just to better match the shape there. An example is that the teeth do this: \__/ but your low poly does this \/ so that can be matched better.
But yeah, the best thing you do is just sort that uv map out, split the islands better, and you will get it.
Ok so here is the update
Also,
I may have missed it in the thread but- what is the target engine? If it for a synced up workflow you can do something like this without needing supporting loops.
You can't really ask those sorts of questions, because the answers will range depending on what it is you're doing, and who you are talking to. For the asset above, I would say even with teeth that seems a "little" high, but thats based on a first person title, with major detail. Then you have lower detail first person games, or third person games etc etc etc...
It all depends on what it is you are doing in relation to everything else. We can only give you suggestions, its for you to see what you can do and how far you need to take it.
I will say this, looking at your unwrap above, it could be a LOT better. You need to be looking at 1:1 pixel mapping, even more so if its for a first person title. You should also keep sections in one piece if possible, like the flat sides of the handle/blade, which means go for a none square texture. In my eyes, its also too low poly (the above shot) and should match the high a lot more, but at the same time, has far too many edge loops... But then these may be there for your engine and lighting pipeline. Like I said, we can only offer suggestions, not give a certain answer.
Given that it is typically something you equip _instead_ of a firearm or similarly detailed model i would say that its fine since a current gen firearm is easily 5000 polygons, and equipping the knife typically means not rendering the weapon you had previously equipped.
If it's never seen up close, then it is way too high.
3500-ish is totally fine. If its for a first person current gen game, its the first person view model, and you wont be rendering another gun at the same type, 5-10000 triangles even wouldn't be entirely out of line(not that I'm saying you need that much). The thing with first person weapon triangle counts - you're generally only rendering 1 asset, so whether its a knife or a rocket launcher, 5-10k or even 15k in some instances isn't going to effect performance on modern hardware in current game engines.
So yeah, 3500 is totally fine for a first person knife asset. For a first person asset like this, you shouldn't be able to see any normal map errors, and you shouldn't be able to see jagged low-polyness of any of your edges.
If the model is a 3rd asset, you've already got too much detail. For a 3rd person asset or prop that will be seen very small on screen, you wouldn't model in the circular cut outs, you wouldn't model in any of the detail in the serrated teeth etc.
Stick a checker texture over it, spplit the UV islands as we have said, use 1 1024x512 texture, move on. Simple as that.
Reading comprehension lol...
When modeling weapons for FPV, you should model the high and low thinking about how the model will be viewed at FPV angle. This means generally giving the scope/sight area the most geometry detail(areas close up in your face should never look jagged and low poly) and texture resolution, it means checking from the right angles so your asset looks interesting from FPV, not just from a side shot(people tend to model guns as if the only reference they have is a side shot).
When presenting its good to show a few angles, but always show a shot from a FPV-ish angle to give an idea of how it would look in game. This is more important for something like a gun than a knife though.
Sorry the other files where currupted before I could post them. But here is the update pretty much the same results as the test just orgainzed. Sorry if I keep beating a dead cat but some of the information was conflicting and as someone trying to improve I want to make sure that I'm headed down the right path. I'm nowhere near the level I would like to achive or that of you all here. And I'm just tring to get a little insight. Thank you for your time and input and I will pay an little more attention to the detials of the knowleadge given here.
I would suggest you back out to before you added any of this geometry. Then UV map this in a way that is sensible for someone to paint on. After that, split smoothing where you have border edges and it is free. Finally, add supporting loops where you need them to control shading.