In this episode of the basic turntable photogrammetry series, I will show you how to bake the Normal Map from the High Poly geometry to the Low Poly one in Substance Painter.
Video Transcript
Hello everyone! In this episode of the basic turntable photogrammetry series, I will show you how to bake the Normal Map from the High Poly geometry to the Low Poly one in Substance Painter.
I will also set up an initial PBR base material, which includes information for the Base Color, Normal, Metallic, and Roughness channels.
First, I create a new project using the Low Poly version of the model as the starting geometry.
I save this project to disk, then import into the project the Base Color texture obtained in the previous episode using Baking in Meshroom.
I add a Fill Layer to the Material, then drag the Base Color Texture into the corresponding channel of the Fill Layer to check the color texture mapping on the object.
At this point, I can bake the Normal Map from the High Poly version onto this new version. To do this, I first click on the Bake Mesh Maps button in the Texture Set Settings panel.
In the Normal section, I set the High Poly geometry in the High Definition Meshes field, then click the Bake button. I will also let Substance Painter bake the other maps because, in general, they might be useful if I decide to use Generators or Filters.
I assign the Normal Map obtained to the Normal field of the Fill Layer. I perform the same operation for the Ambient Occlusion map in its corresponding field.
The applied maps can be examined in the 3D View using the selector in the top right corner, or by repeatedly pressing the C key to cycle through the different maps. You can return to the Material View by pressing M. The intensity of the Normal Map can be adjusted in Blender using the Strength parameter in the Normal Map node.
Since the object is a walnut shell, there is no need to define materials or Textures for the Metallic channel of the Material, which can simply be set to 0 as a uniform value for the entire object.
Regarding the Roughness channel, and consequently the Glossiness channel, it is possible to set a uniform value that reflects the overall roughness of the object. However, I suggest experimenting with materials that have a bit of variability.
I then disable the Roughness and Glossiness channels of the Fill Layer and add a naturally irregular and grainy material, such as Asphalt Eroded Black, increasing its Scale value while ensuring that only the Roughness and Glossiness channels of this material remain active. Of course, this is a purely personal choice.
I chose this material because it allows me to adjust both the average Roughness value and the amount of imperfections, enabling me to achieve a grainy Texture with a selected average Roughness value while maintaining some variation in its appearance.
As you have probably noticed, the Base Color texture has an unpleasant pixelated effect in several areas. This is due to the entire image processing pipeline, starting with the fact that the images were initially captured in JPG format using a smartphone, then assembled and processed in Meshroom. A quick and dirty solution is to apply a Blur filter to the Fill Layer created at the beginning of the tutorial, followed by a Sharpen filter. The best approach would have been to use higher-quality images, but we have to work with what we’ve got.
Some more noticeable errors remain, both in the original images and in the lighting, but for this episode, I’ll stop here! See you next time!