Material textures are easy to overlook, but they play an important role in making your rendered images look photorealistic. This post is the third in a series from expert @MagnusS in the forum. Magnus has been working with KeyShot for 3 to 4 years, and was recently asked to share his advice for how to achieve beautiful, realistic looking rendered images. Read on to discover his tips for nailing material textures in rendering.
This is the stage where I probably spend most of my time to tweak materials. What might be easy to overlook is thatevery material has some sort of texture. Even a seemingly smooth glossy car has a texture. If you look closely at the paint, you can see from the jagged reflections that it has a very subtle bumped texture on its surface. The image below (not a render) shows this well.
Even car paint has a certain level of texture (Note: This is not a rendered image.)
If you aim towards realism, you should start looking closely at your materials and add bump maps and roughness to even your glossy parts. Of course, if you are looking for a very clean "perfect" look, you can skip this tip. A lot of renders aimed for marketing purposes steer clear from this advice. Howeverm I'm a big fan of perfection through imperfection. If you want to create jaw-dropping renders, make sure to give your textures some love.
Now, I've taken the piano model which was a part of a rendering contest here for some time ago. In the pictures below, I've rendered out macro shots (close up) of the piano with and without bump maps and roughness. While the images without the added texture may not seem bad, the added textures greatly enhance the realism of the materials, as seen in the bottom images. Keep in mind that these are very subtle bump maps. I've used the paint material here with a normal map with a height value of 0.015 and a roughness of 0.001. That's all there is for that final push. I recommend seeing these images in full resolution to get the idea. Simply right click the images and open them in a new tab.
Now, some might say they like the clean renders better, and of course when it comes down to it, it's all a matter of taste. Just remember, if you aim for realism:Every surface has texture. The key is subtlety.