Tips & Tricks for Iray for newbies......

Oso3D

For real!

Glancing that, I'd easily think it was a photo, Madbat.

Spit

timmins.william said:

I strongly suspect you are better off shutting off the firefly filter, staying at render quality 1, and rendering at 2 or 4x normal size, then reducing it in post.

Testing that theory now.

Edit: Preliminary, going from Render quality 3/Firefly on to Render quality 1/Firefly off, 10x as fast. Sooo... yeah. Fingers crossed.

Actually, for those of us with only 1G on the card, rendering larger will most likely mean we have to render in CPU mode which will more than offset any gain from rendering at a lower quality. (I tried last night)

Spit

Gedd said:

SnowSultan said:

From what I can find online (and it's very confusing) a typical candle either gives off a luminance value of 1 or 12.6. As I make fantasy images...does anyone have any suggestions as to how to keep things from being absolutely pitch black once the sun goes down? Realism is all well and good, but I could put fifty candles at 12.6 in a tavern and the patrons wouldn't be able to see the food in front of their faces.

I also set the Exposure value to 6, which is apparently within the range of indoor lighting. Not sure what else to try now.

edit: setting Exposure to 0 and the lights to 12.6 gives a little more of what I'd expect from candle light - still very dark, but it's not totally black.

Our eyes adjust to dimmer light. To get the render engine to do that, kick up the ISO to a much higher degree. It will simulate what our eyes would do in low light situations.

Btw, just noticed Spit had mentioned the iris part earlier. The trick is to up the ISO setting to simulate the effect of the iris. ;)

So, ISO it is then. Thanks for that, Gedd.

Spit

Madbat said:

This is EArkham's Zworld basement demo scene. Lit by 5 prop fluorescent lights set to emitter @ 100000 lm temp 5813.15 (I just fudged that)
ISO 400, f/stop 4, shutter speed 60 (I fudged all that too) Architectural sampler on.

Iray INFO - module:category(IRAY:RENDER): 1.0 IRAY rend info : CUDA device 0 (GeForce GTX 780 Ti): 5000 iterations, 17.325s init, 2902.106s render
Total Rendering Time: 48 minutes 42.30 seconds

No I don't know what I'm doing. :red:

Edit: I had a look at the full scene and it doesn't load with the walls behind camera. Since this is an interior scene with no other lights, how does that effect render time (if at all). I'm just wondering how all those bounces going off into space effects things (other than wasted light and likely a darker scene)

Yep, terrific image, Madbat!

I would suspect that not having those walls behind the camera is the reason you needed such high lumens. As for rays heading out to space, yes they do, but they also bounce back from the atmosphere which would change things if iray actually had one perhaps.

I'm remembering back in my Bryce days (tried to start using again but interface gadgets and text are so tiny I can't handle it at all anymore) that there was an imaginary 'wall' surrounding the scene space---IIRC---about 40,000 or 400,000 units away?---which bounced the outgoing light back into the scene.

Anyone? Or am I imagining it?

edit. It would actually be a cube, not a wall. ::rolling own eyes::

Oso3D

I find myself resorting to absurd f/stops, like 64, to get decent shots of full figures from relatively close. Otherwise, say, the face is in focus but the leg or hands further back are out of focus a little.

Am I missing something?

I realize it's not a problem, really, since it works... but it bugs me esthetically. ;)

Richard Haseltine

timmins.william said:

I find myself resorting to absurd f/stops, like 64, to get decent shots of full figures from relatively close. Otherwise, say, the face is in focus but the leg or hands further back are out of focus a little.

Am I missing something?

I realize it's not a problem, really, since it works... but it bugs me esthetically. ;)

What are your camera settings?

Oso3D

Frame width 35.5, focal length 65, focal distance 240, f/stop 64

Madbat

timmins.william said:

I find myself resorting to absurd f/stops, like 64, to get decent shots of full figures from relatively close. Otherwise, say, the face is in focus but the leg or hands further back are out of focus a little.

Am I missing something?

I realize it's not a problem, really, since it works... but it bugs me esthetically. ;)

In regular ol' 3Delight (sounds like a whip topping!) I regularly use high f stops up to 72 to control depth of field. In outdoor scenes I want a little blur, just enough to give the impression of distance without being blatant. But in the basement scene, I was using all that to control light. One things for sure. By the time this is all done and 4.8 is on the shelf, we'll all know a lot more about camera's and lighting than we did before.

I'm liking Iray, it just needs a bit of a different approach. And from what I see , model/texture quality and optimization come into play here. I'm curious as to what all effects render times. I know sheer # of lumens does. Some scenes take longer than others. One reason I suspect (knowing squat about physically based rendering and GI in general) is more surface geometry = more bounces needed. That basement scene actually has a lot of surfaces in it, especially the floor grating. That's modeled, tiny holes and all. Plus there's area above the ceiling tiles, area below the floor grating, shelves, boxes, and floor debris...and whammo, 48 minute render time. I'd hate to think what that would take in 3Delight. I've had render times in days before. I'm thinking that enclosing the space entirely will make a difference. I'll try that as soon as Update Tuesday gives me my computer back. What I do wish for is a second card to run my monitor. When Iray gets working hard, forget about using my mouse. But for some dumb reason my power supply has a bare minimum of plus, so no extra card for me.

mCasual

Szark said:

shame the HDRI backgrounds don't react to DOF as it should, notice the ground under the bike and in front.

it's a bit ( a lot ) of work but using mcjSphericalUV you can project a spherical image onto a "real" plane
i was even able by carefully adjusting ambient/diffuse to get some "real" shadows on that plane
http://www.daz3d.com/forums/discussion/42361/

i only tried it on jpeg images though

Szark

Cheers Casual I will take a look at that later.

Oso3D

My cheat sheet for converting skin shaders to Iray:
First, ctrl-convert Iray Base.

Change the following values:
Diffuse weight 1
Translucence .5
Glossy layered weight 1

top coat:
weight .35 color 1
scatter/transmit
rough .7
reflectivity .5
ior 1.5

SSS stuff:
2 measure
color
measure .5
.3 sss
-.5 dir

Glossy:
ref .35, rough .4, scatter/transmit

Teeth:
Trans .55, white color, gloss .75 scatter only
Gloss refl 1, rough .15
SSS: .1, .99, -.35

Fingernail:
gloss refl .75, rough .4
SSS: .5, .1 measure, amount .3

So far it seems to work fairly well, though I'm still experimenting. I might need to up translucency or SSS

Oso3D

Oh, also, migrate all bump to displacement with, oh, range of 0 min .2 max and subd3. I think.

(Depending on how rough you want the skin -- .2 is fairly noticeable, .1 if you want smoother skin)

L'Adair

Kyoto Kid said:

...need to re render last example. somehow it did not save correctly or to where it was supposed to go and I am not about to waste a lot of time hunting it down

Okay, I'm on page 11 and this tip may have been mentioned already, but...

If you haven't closed DAZ Studio, you don't have to rerender your last image. Just go to the File menu and look for "Save Last Render."

I'd love to give credit to the member who posted that elsewhere, but I've read so many threads these last few days, I simply can't remember. But thank you, whoever you are. :)

kyoto kid

...Daz 4.8 basically crashed. There was no way to save it.

CypherFOX

Greetings,
Just a note, I've been messing with a scene, it's a really cool one, but I had to remove all the plants...and drop subdivision down almost painfully, in order to get it to render in GPU memory. The thing that's been killing me has been subdivision, more than anything else. :(

I ended up having to hide one of two characters (and all their stuff) and render, then unhide it, and hide the other one. The first render was using 3,992MB of my 4GB 740. The second image is currently running, using 3,947MB of that 4GB. Most of the scene is the same, except for the characters and what they're wearing and holding.

I'll put the image up once I'm done, and have composited the images, and stuff like that, but I feel a little wince that I ended up having to keep subdivision around '2' for the characters (one of whom is supposed to be HD), and I couldn't subdivide clothing (and scenery) as much as needed to capture the displacement maps. And that I had to get rid of the plants, because they crashed the renderer. And probably would have used too much texture memory anyway... _sigh_

The underlying set was Merlin's tea garden, and it's evidently more resource intensive than I'd expected...but god the water looks gorgeous. ;)

Anyway, just thought I'd put that note out there.

-- Morgan

mCasual

note that if DS crashes after a render completes

you can go see in the temporary folder

C:\Users\YourUserName\AppData\Roaming\DAZ 3D\Studio4 Public Build\temp\render

and the rendered image(s) may still be there

but next time you open then close DS, the images will be deleted since it's a folder for temporary files

sometimes when rendering animations DS crashes in the
very last phase where it converts the images into an AVI file
( the fault being shared by the codec used )

so using this trick nothing is lost

and you can use virtualDub for the images-to-avi conversion

Oso3D

Yeah, I'm finding SubD is to be avoided whenever possible. Too many objects with it and the computer just locks.

evilded777

So... the G2 presets look amazing in a close up (with just a little work). From a distance, however... not so much. You lose the photographic feel as you pull the camera back.

Any ideas/suggestions on how to retain that realism at a distance?

Oso3D

Are you using Depth of field? That can be key for a feeling of realism.

evilded777

timmins.william said:

Are you using Depth of field? That can be key for a feeling of realism.

While DOF might help the overall realism of an image, its not going to help with the materials... which are the problem. They are amazing in a close up shot, but lose the photoreal effect at a distance.

Zilvergrafix

this needs put in caps:

DON'T CANCEL YOUR RENDER WINDOW!!...or else crash bandicoot!

...use your DazStudio Cancel log panel or whatevah it is named

Richard Haseltine

I haven't had DS crash when cancelling the window - either using the cancel button or the window's close button - but closing the window does lose the render -in-progress, which you might want to look at, so using the progress bar is a good idea anyway. If you do get crashes closing via the render window please report that as a bug.

Zilvergrafix

Richard Haseltine said:

I haven't had DS crash when cancelling the window - either using the cancel button or the window's close button - but closing the window does lose the render -in-progress, which you might want to look at, so using the progress bar is a good idea anyway. If you do get crashes closing via the render window please report that as a bug.

good idea, another bug I found is rendering Aiko3 with angelyna wings...iRay can´t pass of the iteration 1!!!

VoltisArt

Cypherfox said:

I ended up having to hide one of two characters (and all their stuff) and render, then unhide it, and hide the other one. The first render was using 3,992MB of my 4GB 740. The second image is currently running, using 3,947MB of that 4GB. Most of the scene is the same, except for the characters and what they're wearing and holding.

One of my first renders in LightWave, long, long ago on a machine of very low power by today's standards, was an asteroid field. I used a very similar method to fill the screen with rocks in four iterations. The method works quite well to keep memory and processing down, provided you don't have lots of intersecting shadows and co-dependent reflections in your scene. (Shadow-catching objects can help with the former...I suppose reflection-catching objects are possible, but I don't know if Studio has such ability.)

I was not using IBL or a dome background, but rather rendered the farthest cluster of rocks and a star field behind them, then used that render as an image background, hid the stars, switched to rendering another cluster of rocks and repeat. Didn't even have to use Photoshop to composite. :)

Ippotamus

Today's question: Eyebrow masks.
Is there a way to get eyebrow masks working in Iray?
For at the moment, the eyebrows simply vanish.
Using OOT's Fiends.

Tiger Lee Arts

ben98120000 said:

SnowSultan said:

Could someone please explain how you get an interior scene with one emitter light to not be completely black? Do you always have to lower the Exposure value down to 0 or lower from it's default of 13? If I do that, the light emitting object becomes completely white. I expected the Exposure Value to use a base of 0 and we would make small adjustments like with a camera (+1, -1, etc). Why is 13 the default?

Every time I think I'm making progress, it turns out I'm not. Using the sun gives easy and realistic results, but otherwise lights in Iray seem to have almost no strength at all.

Any preset values would be very helpful, I just want something accurate to use as reference and a starting point.

Level 17 scene lit with one sphere primitive with emission shader applied. Iv turned Two sided light option ON, switched Luminance Units to W, set Luminous Efficacy to 100 (in surfaces tab of the sphere).

In first picture luminance is 5000, in second picture luminance is 10000, in third picture luminance is 50000. Rendered in Scene Only Environment mode. The rest of render settings ware default, as in, I didnt tinker with exposures etc.

this was very helpful to me thank very much

VoltisArt

Ippotamus said:

Today's question: Eyebrow masks.
Is there a way to get eyebrow masks working in Iray?
For at the moment, the eyebrows simply vanish.
Using OOT's Fiends.

Yes. When you Ctrl-click on the shader and ignore textures, the alpha map will be preserved. Used on the Genesis BJD brow today.

Oso3D

I'm trying to do some Gen1 characters with translucence, but I keep running into a problem where it appears the edges of the model aren't lining up perfectly.

I'm kind of at a loss... I've tried upping SubD to 3 (didn't help), changing the edge interpolation, changing rendering quality, bupkis.

It works fine in Base resolution, but then shadows look terrible on the figure.

Any ideas, or am I just going to give up on translucence for Gen1?

(Experimenting now with just letting it render a long time and hope it ... undoes it or something)

VoltisArt

timmins.william said:

I'm trying to do some Gen1 characters with translucence, but I keep running into a problem where it appears the edges of the model aren't lining up perfectly.

I'm kind of at a loss... I've tried upping SubD to 3 (didn't help), changing the edge interpolation, changing rendering quality, bupkis.

It works fine in Base resolution, but then shadows look terrible on the figure.

Any ideas, or am I just going to give up on translucence for Gen1?

(Experimenting now with just letting it render a long time and hope it ... undoes it or something)

First, is that Genesis 1 or generation 1 (i.e., Vicky or Michael 1)?

Second, a screen shot might help, but could it be possible that one part of the body has a different or missing displacement map? Base resolution could be blurring out the effect, which shows up when there's more topology to move.

Oso3D

Genesis 1, working on a screenshot now.

Will doublecheck displacement maps when it completes.