IRay Advice/Tutorials?
marble
Posts: 7,500
I've had my new PC for a week now, most of which has been spent tracking down IRay information. The configuration options and permutations seem to be endless and confusing so I have a few outstanding questions which, hopefully, will also help others if we can locate some good information.
1. Best way of lighting indoor scenes with reasonable render times? For example, HDR with some walls and ceiling removed? Or Mesh lights or spot lights with geometry (e.g. 100cm disk)? Should we avoid emmisives? Note: I tried all of these options yesterday and was amazed at the differences to render times caused by some combinations.
2. How to set up materials for products that don't come with IRay mats. For example, many of the G2F/G2M skins don't have IRay sets. So, can we just click on the Uber shader and expect a good result or is there a tutorial explaining how to do it right?
3. The "cost" of subdivision, displacement, bump and/or normal maps in terms of render times. I read that normal maps should be preferred but most of my content does not have a normal map option. I don't have Photoshop on this PC but should I be looking at some way of converting bump maps to normal maps and, if so, how? Also, are all those expensive HD versions of, and morphs for, the DAZ characters too polygon-heavy for IRay?
4. Is there a good explanation of how to use the Canvas feature? It looks really interesting in that tonemapping can be done in post but, again, I don't have Photoshop (nor can I justify the subscription). I believe that being able to edit .exr files is a must but Gimp doesn't have that yet (as far as I am aware).
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Emissives should not really be used for primary illumination...the cost to render times is too great, and when they are used the simplest geometry possible should be used. A combination of HDR (or Sun/Sky and photometrics seems to be the 'best'. It may not be the fastest, but I think it is the most 'natural' approach. Especially if the interior has windows/doors/openings. It doesn't take much goemetric complexity to have an emissive start greatly impacting render times.
Iray Uber is just a starting point. One of the things about many Genesis 2 skins...you can start with the Iray Uber conversion and then match the settings from a Genesis 3 skin that is already set up...but keep the Genesis 2 maps.
The various ways of adding detail...that is really one area where you have to find what works best...not only for your hardware configuration, but also each model/mesh. Iray uses, on average, 3 bytes per pixel for ALL image files....so, do all the maps at 4K actually add up to more memory than a subdivided mesh (that's one question you need to work out an answer to). Can some of those maps be reused? (another one) The Photoshop plugin is not the only conversion tool (I think there are a couple listed in the free software thread in the Carrara forum).
As to canvasses, I don't think exr is the only output choice...just the 'best'. And no, GIMP doesn't have exr (yet...although the 2.9 'dev' series may, I haven't looked lately...2.10 will, but it's probably at least 6 months to 1 yr away). Richard had some good posts on using them...I'll see if I can find any.
I don't know if there's any good exr editors/readers/etc that are reasonable to use other than Photoshop. I struggled with it for a long time, as a GIMP user, before finally giving in.
Most things people do with canvasses could also be done with multiple regular renders. I have no idea if that's more time-consuming.
While tone mapping after the fact is cool, I actually have found myself going back to regular renders and prefer to set up the tone mapping up front to tweak the look I want and THEN render.
Three exceptions:
Depth map. Easy peasy, hugely useful for compositing stuff (like haze or even tweaking 'focus').
Bright skies. Normally, a sun in the sky makes for a cruddy render. Either the sky gets blown out, the ground looks way too dark, or you try to tweak all that and end up with horribly banded/terrible images. With an exr output, however, you have a huge amount of 'room' to work with and can tone map the top down and the bottom up to look excellent.
Node map. With canvasses, you can render something with objects missing. Where they would be, the canvas is transparent. This is, again, useful for compositing. Though it's admittedly something I haven't personally found important very often.
Ok - it seems that Gimp has a plugin to create Normal Maps. Then there are other which look a little too techie (require QT libraries, whatever they are) - these are called Insane Bump and Awesome Bump. Crazy Bump always comes up but it is $90 which is definitely not coming from my pocket. I'll do a bit more research. BTW - what, exactly, is the problem with using bump or displacement in IRay?
I may wait with Canvases until Gimp has the extensions to be able to edit .exr files. I have enough to learn anyway without getting into the more complex stuff.
I found a few IRay skin setting examples on DevArt so I'll read through them too. I'm hoping that DAZ Josh gets around to doing a few IRay Youtube tutorials - I'm always impressed with his contributions.
Oh, I just remembered ... there's also 3DCoat which is a full featured 3D Modelling/Painting program which can bake Normal Maps. I had a trial of it a while ago and was tempted. It also costs around $100 (so-called educational license, but really a good deal for the hobbyist).
AwesomeBump is good and should come precompiled for Windows...no need for extra Qt installs. Qt is what Studio is built with, so if Studio is running, then you can run Qt programs.
So DAZ Studio has already installed the necessary QT requirements? I mean that I wouldn't need to install QT before Awsome Bump?
No, usually a compiled, ready to run program comes with all the needed Qt libraries built in. If you can run one, usually you can run most of the rest. If you are wanting to recompile/build it yourself, then you would need to install the full Qt package.
Never mind - answered my own question ...
Sorry - Didn't see your reply. It works fine - thanks.
No problem...it happens.
But a couple of things about AwesomeBump, as I'm one of the 'early adopters' of it (so early, he didn't even have a Linux build or full build instructions...had to email the dev for specific instructions...the original, first source package was a bit of a mess). I didn't mention it mainly because it is a 'generator' type program for making all the maps from a base diffuse, as opposed to converting existing map types.
It works best with full image maps. Yes, it can convert an existing bump to a normal, but it works better with a diffuse map to start. Unlike a simple 'desaturate and go' map, the processing it does 'fakes' lighting so it is as if you were taking snapshots of the item under varied lighting conditions. While not as good as baking from a hi-res mesh, it's better than the simple desaturate method...closer to a 3D scan. Also, it's best to do one set, close the program and restart it before doing another. It can be a bit finicky when clearing/repopulating the various map slots.
Also, the details sliders...especially for the normal map are very, very useful. The same with the 'step'.
The height map can be either displacement or bump...play with the various settings for it.
For the specularity map, there is a lighting switch...Studio seems to like the 'off' maps better, but feel free to play with that one, too. You can have a very high level of control.
The occlusion map, while not used as such in Studio can become a control map for several things. The metal and roughness maps are usable in Iray.
The grunge feature can be used to add 'dirt' to the diffuse/specular/etc maps. I like using it on the spec and diffuse. Also with some careful tweaking it can do 'edges' and worn patches...but it does take a lot of fiddling around. I usually do those in GIMP.
Shader Map 3 is good too and it's like $50.00... http://shadermap.com/home/
...as to the second part of the OT, are there any good PDF/text tutorials around?
I'm wondering whether experienced IRay users are going through their pre-IRay content and creating Mat Presets for all of those characters, clothing and props. Or do most people just apply the Uber preset?
Can't speak for most people, but I use a number of Iray shader sets that have been created. For a start, Mec4D's Vol 2 and Vol 3 will take you a long way (Vol 1 is good as well). Sveva has a number of "fabricy" shaders on Rendo. Fisty, Parrottdolphin, Khory and others also have great shader sets. Many others but these are the ones I use the most.
Quite an investment in shaders there - I'm going to have to wait for a mega-shader sale :)
As a 98%-Iray user, I do go through older content and reshade it by hand, but only when I'm going to use it. I have plenty of canned Iray shaders for fabrics, and then add my own color maps (often from Filter Forge). I almost never use anyadd-on textures for clothes, unless they're jeans or something special with stitching or designs specific to the clothing, that a generic color map can't easily reproduce. Don't forget there are plenty of free Iray shaders on Sharecg; Parrotdolphin had some giveaways early on.
Folks commonly forget to use the Nvidia MDL examples shaders that come with D|S, and these can often be customized to make them look wholly different from the base shader. There are some good asphalt, carpet, concrete, and metal shaders in there. These shaders do not use the Uber Iray base, so they are simpler to use, with fewer controls to fiddle with. The Red Wax shader, for example, is the world's simplest volumetric shader for Iray. Just change the color, and you've got smoke or fog or poison gas, or whatever it is you want.
It's also possible to get free shaders.
(cough)
I see there are some at PC+ prices too. Also noted the reminders about freebies. Thank you.
I'm starting to come to the conclussion that I'm going to, eventually, have to convert to using Iray so I'm watching threads like this for help on how to start using it. One thing that is really making me shrink back is all the talk about all the things that have to be manually adjusted: lights (holy crap those seem complicated), a billion different adjustments for textures etc. This talk about converting shaders... does this mean that every item that gets loaded into a scene (if it's not pre-configured for Iray) has to manually be redone to something that's Iray compatible? Everything?? Would that mean every surface on a building, every leaf on a tree, blade of grass, every piece of clothing... just what does this mean? That strikes me as a tremendous amount of work per scene. What about things like glass? I see packs with shaders for glass and such, but does this mean that nothing that works in 3Delight works in Iray?
This all seems... wow... this goes way beyond hobby. I do a lot less work at work and get paid for it! Not to mention that reading about all these settings and things you need to adjust (simply for lighting as an example) is complete Greek to me. My mind shrinks back in horror and my eyes glaze over. haha
Where is the friggin Make Art button?!?!
Yes and no. It depends on how the asset was created., and your overall goals The surfaces of many sets share the same material zone, so setting one "leaf" often sets them all -- unless each leaf is a separate object (ugh!) or a sepaate material zone. In that case, you have your work cut out for you, though if you're handy with scripting, you could reduce the time there.
You *should* convert every non-Iray asset to use Iray shaders. Otherwise, D|S will do it for you, which is a convenience, but then you're not likely to get the look you want, or should be getting. You might do this auto-conversion as a quick check to see how the asset might look in Iray, and also to check for issues you'll need to specifically address, such as 3DL "glow" shaders that might need to be manually converted to Iray emissive shaders.
As for the amount of work involved, if it's just a hobby, you can use the auto-conversion when you can, and that'll save time, but may not yield the best possible results. Whether that's accepted to you depends on your aims and artistic goals. I don't do this as a hobby, so the effort invested usually pays off in a better-looking product that doesn't scream "3d render!"
@Tobor - I'm a little confused with what you describe as auto- and manual conversion to IRay. What I do (following the advice of SickleYield in her original tutorial) is select all objects in the scene and all surfaces in the Surfaces tab and apply the DAZ Uber Base (IRay). Is that what you mean by manual conversion? If so, does DS do something similar behind the scenes if IRay is selected as the Render engine? Because, if I don't do the manual thing, when I look in the surfaces tab all the shaders are as they were for 3Delight (unless the product has IRay shaders by default).
I have only just started to experiment with some of the other IRay shaders that are installed with 4.9 but I am quite impressed with the Uber Base shader as a general purpose option.
I've been experimenting with canvases and there are some really interesting things you can do with them. I agree that most of them could probably be done with a lot of individual rendering and creative masking in postwork, but I think that level of work may be easier using canvases.
I think the best way I can describe it this:
You can also break out the surface properties (Diffuse, Glossy, Specular) and only choose to render those, based on either a light source or sources, and/or an object.
This lets you relight scenes without necessarily re-rendering them. See http://blog.irayrender.com/post/37260056351/instant-relighting-nonphysical-effects
Also see:
http://blog.irayrender.com/post/76948894710/compositing-with-light-path-expressions
and http://www.migenius.com/doc/realityserver/latest/resources/general/iray/manual/index.html#/concept/light_path_expressions.html if you really want to dig deep into it.
Automatic means automatic: you do absolutely nothing. When the scene is sent to render, D|S auto-converts everything it needs to into an Iray-compatible shader, called JIT (just-in-time) conversion. You'll see it when it happens in your log. The results can be varied, as you'd expect, and may not be the same as if you blanket everything with the Iray Uber shader.
That said, applying the Uber shader to everything yourself is the preferred method if you don't want to individually change each material -- which can indeed be a time-intensive task. I was responding to a specific question that, no, you actually don't *have* to do anything special to render a scene in Iray. But the scene will look better if you do manually manipulate the shaders, rather than relay on JIT conversion, or the group application of the Uber shader.
Going with what marble said "...select all objects in the scene and all surfaces in the Surfaces tab and apply the DAZ Uber Base (IRay)." is there any way you could post a screenshot of where and/or how you apply the Iray Uber Shader? I have no experience with it and this would be really helpful!
Thanks.
I'm so used to fiddling with materials for everything in a scene in Reality that spending some time setting up IRay surfaces is not too daunting. The difference is that there is a growing library of IRay shader presets - either free or for sale - which was not the case in Reality/Luxrender. I just need to familiarise myself with the surface settings because they don't necessarily equate directly to those I'm used to in Reality. Thank goodness it is not the noodle soup that Blender frightens us with.
You might try the following video by SickleYield. It contains a number of good procedures for use with Iray. Go to about 4:15 in, where she talks applying the default Iray Uber base.
The video is now a bit old, and she made it before the final release of D|S 4.8, so there may be a few discrepancies here and there, but nothing serious.
Thanks for the shout-out!
I have a newer series on Iray that is more up-to-date with 4.9:
https://www.youtube.com/playlist?list=PLJB5iVJzTSqSPdV5UNXUR_yhVozEcxG8O
Excellent. I found these two earlier today:
http://sickleyield.deviantart.com/journal/Tutorial-Getting-Started-With-Iray-519725115
http://sickleyield.deviantart.com/journal/Iray-Surfaces-And-What-They-Mean-519346747
I'll be sure to check out those videos. I'm sticking with 4.8 for now (reading too many horror stories on upgrading to 4.9) so they should be good.
Thanks Tobor & SickleYield!
...still looking for print/PDF tutorials.
I put this document together on the Environment and how I use it. There is probably a lot more that I have missed but I hope it helps a little.
It won't attach so try downloading it from here. It is a Word document in .rtf format.
Environment Tutorial
I've been looking into iray optimization thru render settings...so far, not finding much. :(