PDA

View Full Version : Flicker Reflections?



objuan
02-11-2016, 12:47 AM
Why are these reflections all flickery? Why aren't they flickery in some parts of the object like the loop up top?

The surface has both a reflection map and raytraced reflection, though there is nothing for it to reflect, except for upon itself. Deep.
All of the poly's are tripled. I trying rendering with and without smoothing on the surface, both flicker.

This is an animated gif, click on it to see what I'm talking about
132366132366

Kaptive
02-11-2016, 02:23 AM
It might be worth posting a wire frame. At first I thought it looked fine, but the more you watch it, the more I see what you mean.

My first impression is that because the frame rate is low and the rotation reasonably fast(ish), the changes in direction of the polygons between each frame is quite big, so it'll be pointing in very different directions with each frame.

Solutions might be to render it with motion blur, give it at least a couple of passes.
Also, (and this might help solve it better... not sure) use a flat reflection map that has the same values from left to right... keep it consistant. Like the one below... (just chucked this together quickly to show what I mean)
This might help to keep the reflections a bit more steady. That's all I have right now.

132367

Danner
02-11-2016, 07:50 AM
I don't see any flicker per se, I do see some strobbing from the low frame rate and lack of motion blur.

objuan
02-11-2016, 01:55 PM
Well, it does indeed have to do with my warbled reflection map. I tried changing the scene so instead of the object spinning, the camera and light rotate around the object, thinking then the object would stay relative to the reflection map. It might have helped a little, but not a ton. I guess as the camera angle changes with the flat surfaces and what they are reflecting, you still have the same issue. I guess the loop up top looks fine because it is all rounded so with each new frame a new face is reflecting more or less the same thing, as opposed to the flat faces which are reflecting something pretty new with each 6 rotation.

A solid gradient reflection map would work better, but I prefer the look of the warbled reflection, in still frames at least.

It's no big deal really, thanks for the brainstorming help.

MonroePoteet
02-11-2016, 02:04 PM
You might consider a bit of motion blur and bump up anti-aliasing. As Kaptive said, the low frame density for the full rotation causes a significant angular change between each frame (6 full degrees, specifically), and I think a lot of what might be considered flickering is just a "radical" change in the angle of the object's polygon normals relative to the reflection map. Note that the "horizon" of the torus ring above is quite smooth. Motion blur and bumped up anti-aliasing might make it look smoother at that frame density.

mTp

P.S. Sorry, all of my points were covered earlier in the discussion. READ the thread! (to self)

objuan
02-11-2016, 02:13 PM
orry, all of my points were covered earlier in the discussion. READ the thread! (to self)

No worries. Feels good to have helpful suggestions. Thanks.

spherical
02-11-2016, 04:15 PM
Ah, yes. I thought that the frame rate was coarse just to keep the provided GIF small. 6 per frame is way too large to expect smooth transitions; even with MB. The jump is just too great. Gotta consider the incident angle that increases double to the surface angle change.