Hey guys, welcome back to our 3DX Artist Guide! This month we’re going to be talking about some time saving measures. We’ve gone over lighting, as well as surface configuration. Between these columns and our video tutorials, we’ve gone over lighting, as well as surface configuration. We have our G3F posed, morphed, and clothed to our liking. Save for genitalia, which we’ll go over next month, we should be pretty close to producing a render, right? Well, we’re getting there, but before we take our last few steps, let’s take a sidestep into a related topic. Rendering time! There’s a lot we can do to shave it down, especially when using the Iray rendering engine for Daz Studio. We’ll talk about software configurations as well as hardware options. So let’s get into it!
The three basic rules
In order to crank out a quick render, there are a few things to remember. The first rule is that the more light there is in a scene, the faster it renders out. The second rule is that the fewer light nodes there are in a scene, the faster it renders out. That seems contradictory, right? How can you have more light with fewer light nodes. The answer is simple: environment light! Through adding an environment map, or tuning the global sun settings in the Environment tab (under Render Settings), you can easily light an outdoor scene, or a scene with enough windows. Iray won’t take a lot of time calculating this type of lighting.
But there is a third rule, too: the more surfaces there are in a scene, the longer it takes to render. Obvious, right? So a pinup pose with a girl and environment lighting will be produced in minutes. But that same girl in an outdoor scene like a swimming pool that’s clearly in view of the camera, and all of a sudden Iray has a harder time.
The downside of all this is of course that it doesn’t allow for a very stylistic render. If your scene is more complicated than this, then under the Optimization tab make sure your Instancing Optimization is set to Speed. Under the Progressive Rendering tab, you can further tweak things. The lower your number of maximum samples, the fewer iterations your render will go through before Iray considers it complete. The same goes for keeping the Rendering Converged Ratio at 95%. For each percentage point higher than that, Iray will take exponentially much longer to render an image out.
This can of course leave you with a rather grainy render, but there’s a remedy for that. If you produce a grainy image at a far higher resolution than you intend to publish it at, you can then scale that image down in Photoshop. This will take care of a lot of the grain and leave you with a relatively clean image.
There are also specific effects that will ramp up your rendering time. For example, a Depth of Field or Bloom. Let’s go over both of these quickly.
The way Depth of Field works is it assigns a focal point to your camera, just like how real life cameras work. Everything in that range will be sharp and in focus, everything outside of it will be blurry. We’ll go into how to do this once we cover camera work. For now what you have to know is that Iray has to render this blur. So why not render it out normally and simulate a depth of field effect in Photoshop?
A rudimentary way to do that is to duplicate your render, use an eraser brush on the top layer with a strong feather effect, and take out everything you want to be in focus. Then you apply a gaussian blur effect to that layer (under Filters > Blur > Gaussian Blur), and watch it suddenly work. Of course, real Depth of Field is a bit more complicated than that, but this goes a long way.
The same goes for bloom effects. Iray will allow you to render a bloom effect, which you can finely tune under the Filtering Tab by turning on Bloom Filter Enable. As with DoF, you can go into Photoshop to simulate this effect by using Overlay, Color Dodge, or Screen modes. It’s not going to look as good if you’re not proficient with it, but for any starter to mid-level rendering PC it can make a huge productivity difference.
Which takes us to the hardware question!
We established early on that the rendering engine of choice in Daz Studio is Nvidia Iray. Now, Iray’s speed is determined by the number of CUDA cores it can access. These are what comprise the architecture of your Nvidia GPU’s. As of Daz Studio 4.9, the Iray rendering engine has been updated to support not just Nvidia’s old Maxwell architecture, but also the new Pascal generation. Meaning that with any card labelled GTX 1060 or higher, you can now render in Iray without experiencing crashes and slowdowns.
The reason I bring up CUDA cores is because Maxwell and Pascal cards don’t calculate CUDA core strength the same way. Pascal cards have lower numbers of total CUDA cores, but achieve higher rendering performances. So don’t make the mistake of comparing a GTX 980 to a 1080 for rendering purposes. The 1080 will still win out in sheer processing power, even though at face value it has fewer CUDA cores. The comparison you will want to make is always among cards of the same architecture type. Model 10xx and higher is Pascal. Model 9xx and lower is Maxwell.
The rule of thumb with Nvidia GPU’s is always this: xx60 cards are for average gaming purposes, xx70 cards are a good middle ground, and xx80 cards are designed for high end utility. At the top is the Titan line, which is not only the most expensive but also the most hardware intensive. For rendering purposes, an xx80 card or higher is going to get you exponentially much faster performance. If you absolutely do not have the money for that, a xx70 card is still acceptable.
If you do consider investing in a xx60 card, make sure you verify benchmarks compared to high-end models of a lower generation. That is to say, it might be worth getting a 980 or a 980Ti over a 1060. That will also kick you back to Maxwell architecture from Pascal architecture, so if you intend to plug multiple GPU’s into your system you need to make sure they’re all of the same generation and make. Don’t combine 10xx and higher with 9xx and lower, they just don’t communicate.
More next month!
All this said, utilise your software related options before you start investing in hardware upgrades. To give you an idea of how hardware upgrades translate to increased rendering performance, consider my sets. I used to run double GTX 970’s, and I rendered my October release on those. The average render time for a shot was 45-60 minutes. When I upgraded to my pair of GTX 1080’s and rendered my December set (which is a sequel, so it had the same characters, environment, and lights), my render times decreased to 30-45 minutes.
I won time, but for a $1500 investment I ultimately made a 15-30 minute difference. You can expand on this time by increasing render resolution and downscaling in Photoshop. Be smart about how you implement visual effects and how you configure your lighting. Start there, and then expand out to the hardware realm.
Next month we’ll be talking about genitalia! Yes, that’s right. It’s still porn we’re making, so we’ll have to go over what to do there. We’ll be talking about both pre-made asset solutions as well as what you can do to create your own props. See you then!