Smoothing groups problem (low-poly helicopter)
I'm working on this ka-52...
...and, since it's a low-poly model, I made a little bit of optimization that resulted in small smoothing groups issues:
1) on the bottom in the places where one vertex connects a lot of edges
2) in and around this notch
The question is, how to avoid these problems in case of using smoothing groups for low-poly models? Should I have used different approach (i.e. making a high-poly without geometry issues for baking normal map) or this is ok for low-poly (I know that it's not, but still) or I miss some obvious technique? What is your opinion?
P.S. Also wanna hear critique about this model in general because I am new to 3d modeling and I should know as much as it possible mistakes that I've made.
...and, since it's a low-poly model, I made a little bit of optimization that resulted in small smoothing groups issues:
1) on the bottom in the places where one vertex connects a lot of edges
2) in and around this notch
The question is, how to avoid these problems in case of using smoothing groups for low-poly models? Should I have used different approach (i.e. making a high-poly without geometry issues for baking normal map) or this is ok for low-poly (I know that it's not, but still) or I miss some obvious technique? What is your opinion?
P.S. Also wanna hear critique about this model in general because I am new to 3d modeling and I should know as much as it possible mistakes that I've made.
Replies
Thus the reason for the smoothing/shading errors.
There are a couple of things you can do, all of which are trial by error:
Select the vertices individually and move them manually so they match the same angle.
As you move them you will notice the shading change.
or
Go back to an earlier version of the model that didn't have the groove, and then make the groove using a boolean operation.
By using a boolean for the cut it will be more exact.
Once the cut out area is removed, the surrounding vertices should be at the same angle.
or
Create an additional loop around the the grooves circumference which will minimize the shading -slightly.
or
Create a high poly model and bake a normal map. The shading errors on the low res model may still be there, but when the normal map is applied it should no longer be noticeable. Largely depenadant on the quality of the bake and your cage.
http://wiki.polycount.com/wiki/Vertex_normal
It is likely you will need to edit the normals, plus also move the positions some, plus add a few new edges. Edited normals alone will probably not hide all the smoothing issues, because the normals are basically interpolated in the viewport using linear gradients (look up Gouraud shading).
These smoothing errors are fairly minor though. They will not be very visible if the model is being textured, which most models are.
A normal map baked from a high-poly model can hide these errors, but the baker and renderer must use the same tangent basis.
http://wiki.polycount.com/wiki/Normal_Map_Technical_Details
Could you show on my model where I can add those edges, please? Because I barely can understand how can it help.
james01 made several good suggestions, the third one is probably what's needed in your case. You may be able to get away with less vertices/edges than a full loop.
We have some pics and explanations here.
http://wiki.polycount.com/wiki/Vertex_normal#Smoother_Shading
Little advice. You should add all your supporting edges/chamfers/etc and apply smoothing groups before adding Edit Normals modifier coz there can appear excess normals that will mess your smoothing up.
Keep up the good work. o/
but disappear again after going to upper UnwrapUVW modifier
I just want MAX leave dem normals alone! So guys, please, tell me what to do.
It might be that UVW Unwrap is converting to Editable Mesh internally somehow. Or it could be you need to use Reset Xform, not sure.
Some more info here about preserving edited normals. Not exactly your situation, but might be useful nonetheless.
http://wiki.polycount.com/wiki/VertexNormal#3ds_Max
What I found out:
If I select model with edited normals and go down to Editable Poly and then up to upper Unwrap UVW normals stay edited:
But when I unselect object:
Gonna learn more about xForm.
It is best to keep the modifier stack as simple as possible. Many modifiers (like Unwrap) are dependent on the topology coming up the stack from below... if you change the vertex count in Editable Poly, those Unwraps will all be reset, because the vertex count has changed.
Best to use one Unwrap modifier at a time, and Collapse fairly often.
Also "It is best to keep the modifier stack as simple as possible. Many modifiers (like Unwrap) are dependent on the topology coming up the stack from below... if you change the vertex count in Editable Poly, those Unwraps will all be reset, because the vertex count has changed.
Best to use one Unwrap modifier at a time, and Collapse fairly often." <-- this is very true.
-Unwrap UVW
-Editable poly.
P.S. Woo, gonna texture!
When texturing I use alpha channel as a selection and then painting over it to have nice neat texture. But after applying this albedo/diffuse map to the model these wierd seams appear:
Albedo looks like this:
So I understand that I should paint out of alpha channel edge to solve this problem but the question is: is there any another more elegant way to expand edges of selection?
In Photoshop you can expand your selection/mask by a given number of pixels.
and this in marmoset:
How to avoid this?
Don't think that I'm gonna do something else with this so I can say that it is my fisrt serious model. The major problem is this is a bit too lowpoly and modeled without baking normals map from high poly. What issues else does this model have in your opinion, guys? Wanna hear critique if you don't mind.
AND, speaking of baking normals, could some one help with baking normals to a BOX. Yes Box. I just cannot understand what I am doing wrong.
First of all I make simple box in 3ds max. Then I clone it in the exact same position. Next I chamfer all edges in a clone box and apply smoothing group 1 to all faces. All the faces of the box I add to the SG 1 too. After that unwrap UVs on the low poly box (I tried unwrapping it with default box unwrapper, splitting all faces and by making seams and unwrapping box as one UV piece). Open Render to texture, enable projection, choose high poly, push cage a little bit - all the standart steps. But after applying baked normal map to my low poly box the bloody seams appear (I render in marmoset). If I render it in max the result looks like this: