Green on normal Maps

I was working on an Hk416 for training my skills in game making assets and also i made a High poly version and Low poly version but i made a rough uv mapping by using smart project for testing the normal map but the normals seemed of like have some green-ish colors on it so how to fix it? and tell me what did i done wrong in the making of this model is it the model or the uv

Heres the pictures:



Low Poly Version with normals


Heres The High Poly Version

Heres The Blend File:
https://drive.google.com/file/d/0B3Rjx2fo6X0XZFlzamJyOHBESnc/view

Please tell me how to fix it and show me the steps if there are some major changes that i have to do and also show me what did i do wrong and why is it like that?

also leave an advice and a tips so i can improve my skills on modelling and Uv mapping :slight_smile:


As you can see, it is not uncommon to have green color in normalmaps.
That said, there are still possibilities for problems. “Weird” or better faulty maps can be produced if, for instance normals are flipped. Or the map is baked in some other orientation than tangent space. World space for instance gives usually a lot of greens.
Hope this is of any help for you…

thanks for the little advice but if you download and take a look at the blend files you actually notice that there are some parts with no height difference whatsoever that baked in green even though its completely an even surface like this:


so is this normal or something?

also leave an advice and a tips so i can improve my skills on modelling and Uv mapping

You are right, in theory a complerly flat surface should have just one plain color. But then, every part of your unwrap would have at least some kind of color. Your’s is having many blank spots. Is it possible, that you are using an UV map not matching your bake?
Then another question, what effect are you trying to achieve? As you stated those planes are flat. What’s the point of using NM anyway?

Uv map not matching bake? I dont know what you mean but if you mean by that different uvs for the high poly and low poly one then yes those 2 use diffrent uvs but also isn’t different uvs for the high poly and low poly allowed?

I’m trying to achieve to fix the deformation caused by making the low poly from high poly like in the receiver part near the muzzle there are some edge line that clearly seen deforming the mesh so I’m trying to fix that with normal mapping

Well, the point in using a map is to be able to determin where something is located. Using a map of Paris won’t show you locations in Capetown.

also isn’t different uvs for the high poly and low poly allowed?
When baking it’s not a problem if both objects have different UVs

You just need to ensure you use the correct UVs to apply the normal map as the one used to bake the normal map

Have you tried enabling auto smooth (in object mesh data settings) for the target object so you have flat shading on flat areas and smooth shading on non flat areas of the object

Correct uvs? Yes I used the one that was baked with normal maps

Sorry if I’m still making a wrong point because what do you really mean by correct uvs

Auto smooth? Where is that option? And also arent game assets supposed to be smooth shaded because when imported to the game engine they still gonna smooth it all anyway

yes I forgot to tell that this is a game asset here’s the link

You’ll find autosmooth in the object data panel. ( Mesh panel would be a better name for that. :slight_smile: ) You select your object then enable autosmooth. Set the angle to 180 degress. This will display smooth shading and any sharp edges you’ve marked on the model.

When baking keep both models smooth shaded. Unless you have a good reason for it, don’t mark sharp edges. There are circumstances where sharp edges work. Such as along seams. Where an averaged ( smoothed ) cage would be used to control the bake. But for your set up, keep them both smoothed.

The topology for the high poly isn’t paramount, but the low poly definitely needs to be worked on. You still keep introducing n-gons. While it may not cause many issues for flat/hard surfaces, you’re better off sticking to quads until you get a little more experience. Simplify the construction of the mesh. It’s very hard to select and edit parts for operations like UV unwrapping.

And you definitely need to work on those UVs. There are no rules when it comes to unwrapping. You pick a section and start creating the seams, as if you’re creating a pepakura model. It’s like starting with a finished model, and then making cuts so you can unfold it flat on a table. The thing you need to watch for is distortion. Which is why you apply a temporary UV image( like the default UV grid texture) to make sure this isn’t happening.

Thanks a lot macser
first of all why is N-Gons bad? What does it affect? Is it the hardware performance or something?
Second you said use sharp edges if you have good reason to use it in that case what circumstances do I use it?
thirdly what’s the difference between this autosmooth option then just smooth it from the left option bar?

Thanks for your response macser Appreciate it

Autosmooth takes the place of an edge split modifier. Which you can still use if you want to. It’s visual in the sense that it doesn’t physically split the verts along sharp edges. That’s not a very technical answer. So maybe someone more knowledgeable can elaborate on it.

If you smooth the model from the tool shelf but have no edge split modifier, the sharp edges won’t display in the viewport, until you enable autosmooth and set it to 180 degrees.

N-gons are not bad. And neither are triangles. But if you don’t use them correctly they will lead to shading errors. That’s the part that takes a little experience. For a completely flat surface n-gons or tris shouldn’t cause problems. But as soon as you introduce curvature, things might change. I think that’s the main reason you should stay with quads for now. At least until you get more experience under your belt. A game engine or an associated importer may not interpret n-gons correctly either.

Just being able to select edge loops quickly is a real benefit. It’s also much easier to see the construction of a quad based mesh. It’s more “readable”.

I think for now, your main concerns are the construction of the low poly, and how it’s unwrapped. There’s a lot of unnecessary geometry in there. The rails/handguard are a good example. Try to simplify the mesh where you can. I did a quick edit on the back part of the rail to illustrate what I mean by that. I marked some edges I’d suggest for seams. Obviously that would continue down the length of the rail. The reason being is that those areas aren’t very visible and would have a naturally hard edge anyway.

Attachments


And last question why is some part of my mesh baked in green even though that part was completely flat is it my fault that I did a bad modeling and baking? Or is there some important steps I missed? Cause i already check for flipped normals and recalculate outside and also I read that some people solved this by changing the bias and distance properties of the bake I want to try it but will it affect the normal map quality?

Thanks for your response

The color appearing in your map isn’t determined by the “flatness” ( is this even a word?) of the face in question. But the direction of its normal. So yes two completely flat faces can have different colors. Even shades of green.

Ok. I’m not the best person to give technical advice. So I’m open to correction on any of this.

Heavy gradients on a surface that should be flat is not the best result you could hope for. Although there should be some red, green and blue, as they serve to mimic changes in angle. In practical terms, red representing light on the X axis, green on the Y and blue on the Z.

With that said there’s a potential problem before you consider going to the baking stage. Namely mesh construction.

Let’s take the stock on it’s own, for example. A hard surface model can benefit from keeping the mesh very simple and allowing the sub-surf modifier to do the rest. Packing in loops can lead to pinching and hard lines appearing.

I’d advise leaving the sub-surf modifier on by the way. There’s no reason to turn it off, or apply it unless it’s specifically called for. There’s rarely a time when edits won’t be needed. Keeping the modifier on and keeping the base mesh simple makes that far easier.

This section is going to be picked up and transferred to the low poly. So you need to address this. Here’s how I would approach it:
https://2-t.imgbox.com/Yd4wgTVJ.jpg https://6-t.imgbox.com/QgtiUGdx.jpghttps://1-t.imgbox.com/rkYoCH8v.jpghttps://8-t.imgbox.com/napgpBAT.jpghttps://3-t.imgbox.com/R4372mIz.jpg

Obviously that can be refined. But don’t add any more than you need.

You can take my advice or leave it. But I think you need to concentrate on constructing the meshes to remove shading errors first. Then move onto baking when you get more confident with that. Don’t be discouraged by making mistakes though. You learn from them. :slight_smile:

Sorry for the long response but i had to Unwrap the mesh and thanks for the informations and tips guys its really Helpful and helped me solve it im now on texturing part real thanks for macser :slight_smile: