Well, I'm not even trying to launch a discussion about Maxwell here.
Let's come back to my initial question because I still think it might be a
good approach to convincingly fake DOF in post.
There must be a way to let mental ray translate reflection ray lengths into
a grayscale image, no? Or am I making no sense?
Ray 1 travelled infinetly far (hit the environment) -> make that pixel
black
Ray 2 travelled 100 scene units (this is the longest ray) -> make that
pixel black also
Ray 3 travelled 80 scene units -> make that pixel a dark gray
Ray 4 travelled 50 scene units (half as far as the longest ray) -> make
that pixel 50% gray
Ray 5 travelled 20 scene units -> make that pixel a light gray
etc. etc.
Gent Krasniqi schrieb:
well md_aperture gives convincing results if you use enough samples and if
you're willing to accept the rendertimes. Let's not forget that with
maxwell you're looking at ~ 20 hours (on an up-to date system) for the noise
to clear up on reflective surfaces such as in this case.
This is a typical scene where a renderer like Maxwell will turn out largely
'undisputed' superior renders, because it is what's it advertised to be.. a
simulator. But you'll have to pay in someway with every renderer, in
maxwell's case its rendertime.
Though I think that for fields such as product visualization etc, that
require highly realistic stills, it probably is the best choice.
On 8/14/06, Christian Götzinger <cg(at)pension-goetzinger.de> wrote:
> Hi,
>
> I didn't try md_aperture, but last time I checked it didn't really give
> fully convincing results. I might want to give it another try, though I
> think it may be too slow.
>
> As for the reflections in the rings - I saw your image in the CGTalk
> thread. If you compare that to ThomasAn's image directly above it
> becomes obvious that the reflections in the two rings are not blurred
> because of blurry reflections. You can clearly see out-of-focus
> highlights that are caused by the depth of field. These are missing in
> your 2D solution which is why your version looks flat.
>
> Furthermore, the challenge rules state that both rings are supposed to
> have "high gloss reflections" - only the main bodies of the coins are
> supposed to have very blurry reflections. But as you have seen, even by
> bypassing the rules and making the reflections blurry you cannot
> simulate the rich look of out-of-focus highlights.
>
>
> Gent Krasniqi wrote:
>
> > Did you try md_aperture? There is a spdl somewhere at cgtalk. It's
> > still slow (like 3d dof in 'most' renderers) but has more control like
> > aperture shape etc.
> > BTW, alot of the 'sparkle' in the reflection of that gold ring is
> > caused by the gold ring not being perfectly reflective (alittle
> > roughness) and high gloss. Doing a render of that scene right now and
> > will post a mental ray result here.
>
>
>
> Apparently it originates from Maxwell Render. If I recall correctly
> however, I've seen similar quality come out of VRay in this thread.
> I don't want to majorly dwell on this particular image however, as it
> was just supposed to be one example for an area where I can't seem to
> get convincing results out of mental ray.
>
> By the way, I did try X-DOF on this scene back in the day, and the
> results were absolutely horrible, they screamed "post DOF".
> This is especially annoying because X-DOF's Lens Shader seems to
> calculate everything correctly (the reflections become way more
> defocussed than the ring surfaces), however the X-DOF Output Shader -
> which is supposed to wrap everything up - doesn't care about this and
> incorrectly adds the final blur based on Z-depth, not on ray length.
>
>
> Steven Caron wrote:
>
> > hey christian what renderer did this image originate from? just
curious...
> >
> > steven
>
>
>
>
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