Introduction
This time I mainly need to draw textures and display them in Maya. I have always felt that drawing textures is not a complicated thing, until I encountered many problems this time, because for the first time I used a high polygon model to bake normal textures.
Process
My graphics card is GTX1060 6GB, obviously this may affect the operation of Substance painter. But I chose to ignore it first
When creating a new project, I kept the PBR of the template, but this time I forgot one thing. I need to change the normal map format to DirectX. In this map mode, the Y axis is up, and openGL is Z axis up.
Under the baking texture menu, I imported the high-quality model, and then ignored the cage and distance, but adjusted the number of texture samples, and then selected baking.
This was only the first time I tried, and I knew that there would be a bunch of problems:
- The resolution of the texture is low and the aliasing is obvious.
- The model has black edges.
- The model cannot be baked separately, and the textures will overlap.
- There will be bumps where the models alternate.
At this time, the problem that I did not solve last time comes. What should I pay attention to when unfolding UV and baking?
https://www.bilibili.com/video/BV1Qo4y1D7Rk?p=7&spm_id_from=pageDriver
https://www.bilibili.com/read/cv804325/
The purpose of baking is to record the normal information on the high-face number model of the object as complete as possible. The three elements for baking well are: smoothing group, UV and Cage.
- Smoothing group and UV
This is called soft edge in Maya. If two faces share an edge and share a smoothing group, they will be rendered as smooth surfaces. Each patch can contain no more than 32 smoothing groups. The normal direction of the faces in a smoothing group at the vertex where they intersect is the weighted average of the normal directions of the three faces.
The difference between soft edges and hard edges is that we can see from the picture that the points on the hard edges have four vertex normals, while the points on the soft edges share the same vertex normal.
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As shown in the figure above, cubes No. 1 and No. 2 belong to the smoothing group. After they are rendered, the edges are smooth, but the faces are not flat and the contours are bad.
No. 3 and No. 4 are not smoothed. After they are rendered, although the surface of the cube is flat and the outline is clear, black edges appear on No. 3, which is not fully expanded by UV. The culprit for this black line is the bleeding of the normal information between the faces caused by the lack of separation of UV. The solution is to cut the UV at the junction of the sides, and then separate a certain distance.
- cage
Cage is the option I ignored in SP because I didn’t create a cage.
During baking, the face of the low-face number model emits rays. If two adjacent faces are at a 90° angle, the rays will not pass through the corners of the two faces. The role of cage is to allow rays to also pass through the weighted average direction of the two surface vectors, passing through the corners between the surfaces, so that the low-surface number model can obtain the complete normal information of the high-surface number model.
When making a high-surface model, in order to make it easier for rays to pass through the corners between the surfaces, the details on the high-surface model should be careful to avoid the two connected surfaces being perpendicular to each other, and the chamfer should not be too strong.
Okay now back to the topic, how should I solve my problem?
- Adjust the sampling distance of baking, but this cannot solve any problems. 10
- Adjusted the resolution of the texture. I only had 540p before, but this time I changed it to 2k, which solved the problem of insufficient resolution.
- The formation of the black edge has been explained above because the hard edge is not separated. At this time, I can’t go back and modify the model, so I can only give up. Next time I will remember that the hard edge will be separated.
- The wrong edges baked out of the overlap of the model can be deleted in Photoshop. Of course, if possible, render the objects separately as much as possible.
Of course, I also tried to modify the normal seam error directly in the SP. There are two main methods:
https://www.bilibili.com/video/BV1Xy4y157v1?from=search&seid=7696895823833908232&spm_id_from=333.337.0.0
https://www.bilibili.com/video/BV1NK4y1g7WJ?from=search&seid=7696895823833908232&spm_id_from=333.337.0.0
Unfortunately, neither of these two methods can solve the problem I raised. This also tells me why the UV edges need to be separated on the edges that are not easy to see, because the lines produced by the seams are not easy to remove.
You have found out, I have mapped the skin. Yes, I referred to this video:
https://www.bilibili.com/video/BV175411G7D4?p=10
She found a lot of references first, such as the skin map of the human face, the blood vessel map and so on. She first applied the basic color to the skin, and then she applied red to the nose, lips and ears to show people’s vitality. Then she used purple and yellow to highlight the turning points and flat areas respectively. Finally, some cyan highlights the feeling of blood vessels. In addition, she also drew thickness maps, but I didn’t add so many details because of the lack of accuracy of the character.
Here I want to remind myself that the next time I draw the texture of the eyes, I must use a separate UV, because the accuracy of the eyes cannot be placed in a small texture.
I used the same method to draw pants and shoes. By the way, I mentioned that the performance of my computer doesn’t allow me to sculpt high-face number models well, so when I draw textures, I use alpha and height to draw as many details as possible. twenty four
I am also very happy that SP provides ready-made shaders to help me draw sweaters and weapons!
This is the texture I drew in substance painter.
When I opened Maya, the most interesting situation happened-I couldn’t find Arnold! ! ! It has always been here, why is it not in my Maya! ! ! Fortunately, after looking up the information, I determined that Arnold was closed. I just need to open it in the plug-in manager.
Next are the steps I want to do:
- Select the model and create standsurface.
- Import the color map (diffuse map) in Color and select sRGB.
- Import rough map in roughness, select Raw, and switch on alpha is luminance.
- Import the emission map in the Emission color, select Raw, and remember to see if the weight is adjusted higher.
- Import the normal map in bump mapping, select Raw, use as tangent space normal, and switch off flip R &G channel in Arnold. (This is more complicated, you must remember)
- Import opacity map in opacity and select Raw.
- Import matal map in Metalness, select Raw, and switch on alpha is luminance.
God, I tried many times and I keep running into problems!
I accidentally selected object space normals in bump mapping, which caused the model to turn black once I rotated the model.
Yes, it’s still a normal map problem. I forgot to switch to a raw file, so the normal map let my model
It becomes black on one side and white on the other.
When importing the matal map, I didn’t switch on alpha is luminance. To be honest, I don’t know what this controls, but once I switch it off, all my models become metallic.
In the emission map, my weapon is black, so I return to the SP check. The default steel for the normal is to turn on the black emissive. I couldn’t laugh or cry and re-exported the texture.
Next is the model I completed in Maya:
Conclusion
In the drawing map here, I learned new knowledge. After all, this is the first time I have baked a normal map with a high polygon model. I made a detailed note explaining the principle of unfolding UV and the issues that need attention. All in all, my model is not difficult, there have been so many strange errors, but fortunately, I have the patience to check the information a little bit, and successfully solved them.