Update on Chapter 5, Part II

Hey guys, just a quick update on the artifact problem I had on my “room with a window” rig, back in part II of chapter 5. I e-mailed the author about it, and not only did he explain what the problem was, but he also provided a couple of solutions to the problem, one better than the other. Ay, Doublyou, Ee, and then Some.

Remember the artifacts I was talking about? The image I showed you was half-solved using that smoothing trick, but without it it was much worse:

See those room edges and the top of the left chair? Not pretty.

So get this: the problem is in the fact that we’re using buffered shadows with our spot lamp that’s playing the Sun. The way it produces those buffered shadows is by using a depth buffer, and this buffer doesn’t have enough detail to catch the edges of the room. So sometimes those artifacts happen. How do we solve this? Well one obvious way is to use ray shadows instead of buffered shadows, but that’ll cost you a lot of CPU cycles. Another way, is to add sort of a shield outside the room (and away from the camera perspective) so that it casts a shadow on the edges where the light is leaking. I just extruded the outside of the window for this, but if you’d feel dirty doing that or have enough time on your hands, just go ahead and add thickness to the walls like a proper room would have, and that will solve the problem. Here’s the result:


That’s what I call customer service!


This post is part of a series on the book Blender Foundations.
You can find the base post of the series here.

Next post on the series: Chapter 6 (Character Creation), Part I
Previous post on the series: Chapter 5 (Lighting), Part II


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