cujoe_da_man opened this issue on Jan 06, 2017 ยท 16 posts
bagginsbill posted Sun, 08 January 2017 at 9:18 AM
Oh and the subject of ray bias was raised, although it has nothing at all to do with jade per se.
The FireFly engine has some peculiar issues having mostly to do with smooth shaping of polygons. The problems created by flat polygons pretending to be curves appear when you use displacement, subdivision, or the FireFly "smooth polygons" options. CG is full of cheats and approximations in order to gain speed. The numerous cheats and fakes in FireFly geometry can occasionally produce artifacts in the raytracing reflection and refraction calculations. So all the raytracing nodes have a ray bias feature, which basically is another artifact to counteract other artifacts. Basically it makes a point on the surface ignore other nearby parts of the surface. These parts are sometimes not real but instead they are failures of the geometry approximation algorithms. Visual artifacts (flaws) are often produced by reflecting into fake geometry that also happens to be really close. Simply ignoring that fake geometry when it's really close is sometimes a less offensive artifact. Exactly how close is close? That's what you get to answer by setting ray bias. If you ask what's the right value, the answer, unfortunately, is "it depends". Anyway, the values I use are displayed in inches because my Poser Display Unit (known as PDU) is set to inches. If you're copying a screen shot of mine, you need to be constantly aware that a number in a different unit system is a different number. If you have your PDU set to feet, for example, and you type .3, then you really mean .3 * 12 inches which, on my screen shot, would actually be 3.6 and that is NOT a good value for ray bias.
However, in your scene, where you have an isolated sphere with nothing to reflect but itself, any value of ray bias will look pretty much the same. So bringing it up was not going to address anything going on in THIS particular image.
Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)