- Jan 15, 2018
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As time goes on it's easy to find new things that rub you the wrong way. And here, we're all about rubbing you the right way. So what can be done to fix things like surface textures in order to increase their quality and match other objects/scenes in your renders?
To start, what are textures? In the 3D world everything is made of polygons. It could be as simple as a square that creates a flat plane like a wall. Or it could be many polygons connected together to form complex shapes like a person. Then we take a 2D image and lay it across these polygons, sort of like wrapping a present, that gives the object color.
But these texture maps can do more than add color. They can also show how rough or reflective a surface is, and even simulate additional geometry that doesn't exist on the polygons.
This brings me to the issue I recently faced with a brick wall where I have a closeup scene.
From a distance there's really nothing wrong with this brick wall. But when we're up close I had two problems. First, the resolution detail is poor. Second, it's lacking the depth of how bricks protrude out from the mortar. With Emily standing nearby, it's easy to see the difference between her finer details compared to those of the wall. It's almost as if the bricks are painted on rather than real physical blocks.
At first I set out to solve the second issue in hopes that it would improve the first one as well. And so the first thing I tried was something called Displacement.
As I mentioned above, some maps can be used to simulate additional geometry. Displacement maps, in particular, actually create new geometry on a surface.
Doesn't look impressive, right? When you look at this image, it seems like a low quality brick pattern. But what the grayscale is telling the render engine is how far forward/backward that pixel protrudes from the surface of the polygon. In other words, it calculates extra geometry by cutting that polygon up into much smaller polygons at the time of rendering, and creating an unevenness.
There's a second type of map that simulates extra geometry, but doesn't actually create it. Those are Normal or Bump maps. Both essentially do the same thing, just in different ways.
This is a sample of a Normal map. They work similarly to the Displacement maps in that it tells the render engine how far forward or backward that pixel protrudes from the surface of the polygon. Except instead of splitting the polygon up and creating extra geometry, it only calculates how the light reflects & casts shadows on itself IF that extra geometry existed.
So what do these effects look like?
Here we have a sample with no Normal or Displacement maps used.
Next, we add in the Normal map which will give it the illusion of being more 3D.
And finally, we add in the Displacement map which actually creates extra geometry.
Big difference. Pretty impressive just for an ugly gray map image.
There are extra steps needed in order for Displacement to work, such as making sure the surface can be broken down into many subdivisions that will be small enough to form the extra geometry.
After trying a few options with the original brick wall, I wasn't happy with the results. My hope of adding displacement didn't overcome the lower resolution of the Diffuse (color) map as much as I hoped.
So in the end, after trying many combinations to get the red/brown bricks to work, I opted to switch them out for the modern looking beige ones. It's not what my original vision was, but I had to pivot into something more fitting. And I think it looks better.
Emily thinks so, too.
