It’s a Bright Day with Iray — Trying Out DAZ Studio 4.8

There has been a lot of excitement about the beta release of DAZ Studio 4.8 Iradium, which features Nvidia’s Iray render engine. There’s been a fair amount of confusion too as we all begin getting to grips with this. Maybe you are one of the people already turning out impressive renders, but have no fear if not, there are many more of us still finding our way. I bet there are a good many too who have decided to wait and see.

Being a vendor now as well as a customer, I was conscious that every day I put off exploring Iray, I was slipping behind on something that I’d have to learn sooner or later. So DS 4.8 was duly downloaded and installed, and the handy tutorial from Sickleyield’s DeviantArt journal got me started with the appropriate render settings. I recommend you take a look at it too, there are a few relevant entries there so the link takes you to her account where you can then browse through the March posts.

The first hurdle, at least for me, was getting my head round the different ways of lighting an Iray scene. I’m not going to ramble on about biased versus unbiased, you can find that information better explained elsewhere, and I’d only be paraphrasing. However, the thing you need to know is that Iray lighting is more ‘real world’. If you have a photography background you’ll like this. You might also like, as I do, the use of date and time to position the sun and get a realistic sunlight effect for the time of year (and day) that you specify. OK, I admit, it seemed complicated at first, and it does frustrate me that I can’t seem to save new defaults. But being able to reset the sun to your own location is a cool feature.

You do this in Render Settings > Environment, scrolling down to SS Latitude, SS Longitude, SS Day, and SS time. If you don’t see these options, make sure your Engine at the top of the Render Settings pane (Editor tab) says NVIDIA Iray. Before you even touch these settings, select Sun-Sky Only for Environment Mode right at the top of the pane’s options, and make sure you set the UTC Offset too. I happily did a whole sequence of renders only to discover that it defaults to the DAZ 3D office location at -6 hours. Well I’m considerably further north than Utah, and a good way east too. Check your own time difference from GMT, if you have one (don’t forget about summertime adjustments). You can find out the correct latitude and longitude for your nearest city online and input those. Date and time are self-explanatory, but if you are in the northern hemisphere you’ll probably want to start with a day in summer.

If you don’t like this way of lighting, look instead in your content library for Render Presets > Iray, and from there select the Sun Dial Set to load it. By expanding Sun Dial in the Scene pane, you can select the Sun Chain and then in Parameters change the Elevation and Azimuth to get the sun direction you want. By the way, if you want a quick preview of what’s happening with the lights in relation to your model/scene, in the viewport corner dropdown where you choose from options such as Texture Shaded, Wireframe, and so on, there’s now a new NVIDIA Iray preview option.

The third way of lighting your scene is to use HDRI images, with or without the dome. I haven’t experimented much with this but you can get HDRI images free online and you might have some already, e.g. in the HDR packs by DimensionTheory. The Yosemite ones are included in the Platinum Club. If you need further tips on HDRI, I’d recommend you stop by the forum. (Update: or you could look at this useful post by SnowSultan on DeviantArt. SnowSultan is the creator of the popular Smacky character and an all-round terrific artist… nice guy to talk to too.)

Checking the forum would currently be my advice on shaders too, as that’s where I picked up the tips for skin and hair shaders that I’ve since experimented with. At this stage, everyone is breaking new ground and there’s no hard and fast way to do something. If you are happy to adjust dials and re-render many times, you’ll start figuring out the settings that work for your own character, scene and lighting.

Rendered with the Iray Engine

Rendered with the Iray Engine

I know, there is nothing so predictable in 3D artwork as a female portrait. However, I wanted to keep it simple while I was figuring it out, and it made sense to start with skin and hair settings.

The character here is a new favourite of mine, based on the recently-released Aneta, though you’ll find Aneta out the box is younger and more classically beautiful than my version. I always add my own changes.

It took a fair bit of work until I was happy with her in Iray. The skin settings I used were largely those shared by Kamion (who has a talent for character work) in the DAZ 3D forum, with some tweaking. Hair settings were also gleaned from a forum thread, with the most important tip to pass on being that you’ll need to find Cutout in the surface settings and increase it to 1.5 or more if the hair looks too thin when rendered in Iray.

Rendered with the 3Delight Engine

Rendered with the 3Delight Engine

I couldn’t do a direct comparison with 3Delight because each render engine uses different lighting. I believe they can share the photometric lights so if your light rig uses those you can try your own comparison. I did keep the same model and pose to render in each though, and it was interesting to see the differences.

The 3Delight render, being CPU-only, took around 3 times longer than my GPU-only Iray one. The skintone is a shade lighter in the Iray one. You’ll notice her dress is also more washed out so this is more a result of the lighting than a shader issue. While I didn’t play with the exposure settings I imagine they’d take care of that.

None of my work could be called photoreal and that’s not my personal goal, but I feel the Iray render is a little more natural looking. Whether that’s good or bad is a matter of opinion.

Clearly the colours are richer in the 3Delight one, despite the dress having an Iray shader, and I think it is also more flattering to the model. Her eye makeup is softer and her eye whites are nicely shaded. On the other hand, the lighting is sunnier and more believable in Iray, with no need for artificial eye reflections. A black shade of hair isn’t easy to get looking natural in any render engine, but personally I feel the Iray one has the edge.

I’m not stuck on the fence here. Rather, I can see definite advantages to both render engines with their different capabilities and lighting options. Ultimately a render engine is a tool, just as a camera is. Some will rush to stand behind a banner, as they do with Nikon vs. Canon, but if your system can handle both then you don’t need to choose. Just use the best tool for the job at hand.

On the other hand, if your current setup means you are ‘stuck’ with 3Delight, don’t feel too aggrieved. It might be me but I think it is looking better than ever in DS 4.8. In any case, the artists who produce characters for DAZ have spent years getting to know how to make them look their best in 3Delight. That means you’ll continue to get great results straight-out-the-box. There’s definitely something to be said for that.

If you can, though, give Iray a try. Don’t expect instant photorealistic results but just have some fun playing with the settings. If you come up with a winning combination and feel like sharing, we can’t wait to hear from you over in the DAZ forums!


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About Indigo

As a digital artist on a budget, I'm fascinated by what happens when art and technology meet, and love discovering affordable ways to make that happen.
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