More then once my final renders have blotches, spots, and white and black stains...especially on wall surfaces...i have tried and fiddled with all the options in the render settings, lowering and also increasing them one by one...but nothing improves the render quality.  I use different light sets and domes that take advantage of indirect light.  I dont know why this happens...nor how to solve it.  One thing i do know for a fact...and that is that in Daz Studio this problem is non existant...i have used Studio in the past...and i have never seen these imperfections in final renders...hmm...wonder why that is?...

Any insight would be helpful

Thanks for viewing.  ( please click on image for full view)

God bless.

I think there were a number of threads on the use of IDL and artefacts appearing in corners where there were sharp edges, IIR if you do a search for posts by bagginsbill on render artefacts you might find the answers there.........

Make sure you're running Poser service release 3.1, first off.

See this thread perhaps:

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3969705&ebot_calc_page#message_3969705

You will possibly need to turn off Irradiance Caching for Indirect Lighting, if what you're rendering is displaying these splotchies...

Yes, turn off IC. Also, the better the quality of IDL, the less splotches you get. What you've described also happens more often when you use emitters rather than standard lights - something I really hope they fix in the next version ;)

Laurie

Did you have the "indirect light quality" slider all the way to the right?

I see two issues here - first, light leaks at 90 degree corners on geometry and secondly black smudgy splotches. I found a workaround for light leaks - see post here http://forum.runtimedna.com/showthread.php?74474-Backlighting-in-Poser at RDNA. That looks like Jack Tomalin's Classic Deco set, so if you can't alter the geometry I'd suggest trying a couple of high-res square primitives placed behind that area and facing out - haven't tried this myself but it may be worth a shot.

Black splotches - if you increase Irradiance Caching in the render settings to 100 it should (if I remember right!) dispense with the IDL pre-calc pass (ie. no pass with red dots). Firefly will include IDL in the main render pass using brute-force computation which is the most accurate method (ie. fewest possible artefacts) but is also slower - a lot slower. Whether this is a viable option depends on the speed of your machine, the complexity of the scene and your patience!

Finally if you're using an emitter in the scene, how big is it in relation to other objects? Smaller emitters produce more splotches than large ones if I remember correctly.

increasing IDL samples (d3d FFRender script) may reduce frequency of blotches.  no IDL precalc (IDL IC =100) may only reduce their size, but worth a try IMVHO.  drop shading rate to 0.2, incr. IDL bounces to 16, incr. pixel samples to 16, incr. refl. qual to 1.0, et al.

for those waiting to learn size of emitting surface in OP's render, it's bill's envsphere and lamp domes.

p.s. caisson, thx fr lnk to bill's BBeye.  I had crossposted in earlier thread.  my suggestion to bill is to incl. link in readme.

( blimey this isn't art, it's horrible science... )

Quote - ( blimey this isn't art, it's horrible science... )

There's an art to the science... or is that a science to the art?

Thanks Miss Nancy, for a concise breakdown of the other parameters to look at, I think.

While that brute force, no IC approach, can apparently deliver less artifacts, the cost in time can be significant.

I tend to go with upping the IDL bounces, IDL samples and pixel samples... and lowering the shading rate too.

However, in truth, I mostly render with at least one Infinite or Point light, bring the IDL Intensity down to 0.5 or below for exterior... maybe a little higher for interior, then go with between 4 and 16 IDL bounces, IDL samples 200, IC 42 or so, pixel samples 7 or 8 and shading rate of 0.4.

Relatively fast to render a straight forward-ish scene... and no splotchies generally.

I can still get red dot or black dot (not splotchies) artifacts sometimes, with that approach.

Sometimes that, separate issue, is the ray trace or IDL bounces being too low I think, also?

other issue bill mentioned in re: IDL attenuation bouncing off diffuse surfaces.  IIRC he said to drop IDL value to 0.1 or 0.2.  we know we may get light multiplication in occluded areas if diffuse surface values too high or if IDL value > 1.0, but bill was saying even 0.8 (original value recommended by stefan in first release of IDL (poser 7)) is too high in current version(s).

I was hoping that particular thread would get a sticky up at the top there on the first page. It was a good thread and I believe merited further discussion.

Attached Link: D3D's Firefly Render Script thread - OP RedPhantom

Attached is the link to the thread I think we're talking about here?

I'd agree, it was a very informative thread.

yes, that one.  bill said it would make occluded areas look better, and those are where we see errors in OP's render.  they may put a sticky on it, but poser features have a way of changing, as in "always use AO" thread.