Tako Yakida World - CG art using DAZ Studio, Hexagon, Carrara, LuxRender, Reality and Photoshop Elements 9



Outdoor lighting with a great free prop.

Posted on May 4, 2011 at 6:46 AM

Today I want to introduce you to an excellent prop called "Sponza" created by Marko Dabrovic and now offered to the public free of charge at Crytek.

It is an excellent testing ground for the Reality plug-in and the LuxRender rendering engine. This is because of it's rather narrow construction. You can't just slap a sun into the scene and expect to get great results. Of course, it is almost that easy. I will show you in this tutorial how I was able to get the below result:


Of course, a lot more went into this scene than just placing the sun, but I don't want to overwhelm you with all the details. So for now, we will keep this is simple as possible.

First, due to the narrowness of the space, I was having trouble with the perpective view in DAZ Studio. The view kept going into the walls as I rotated around! Well, to fix this, I simply created a new camera and changed it's focal length to 35 millimeters. (See below highlighted portion.)

Now I could rotate around without running into any walls!

Next, I created a sun using the Sun Light in the Reality Light folder,  then loaded a diffuser from the Reality Prop folder. (How nice that you don't have to make these yourself anymore!) What's a diffuser? It's a device that spreads the light particles so they become nice and soft. It will load into Reality as a Matte Translucent material. What's "matte" mean? It means it's not shiny. Pretty deep, huh?

By the way, with the Sun added, I was having trouble seeing my objects to work easily with them in DAZ Studio. To fix this I added an UberEnvironment light. From my experience Reality ignores UberEnvironment, so it's no big deal if you forget to delete it later when you are ready to render. After all, you might need it to tweak things a few times.

When I was ready to load Reality, I selected an object on the flagpole so that I could set the camera's focal distance to it. In other words, this is the distance from the camera to the point where the image will be sharpest, or most in focus. This time I selected the pin that the doll on the right was holding.

Also notice in the below screenshot that I preset the exposure controls for the camera. What that does is tell your Lux rendering engine to have your light levels where you want them to begin with. Without presetting, it can become quite a pain when you have to keep resetting these values in Lux itself after tweaking something in DAZ Studio or Reality. (Also see my earlier tutorial for a note about f/Stop near the bottom of the page, just above the last image.)

So, I set the diffuser's alpha channel strength to 0.91...

...and set the tranmission color to light gray. (Transmission color is what color the light is that passes through the material.)

Back in DAZ Studio (you can do this in whatever sequence you like) I resized the diffuser and positioned it perpendicular to the direction of my sunlight, which you can see below.

And here is a shot from the Sun's point of view (with the diffuser hidden so you can get a better idea of the light's relationship with the Sponza prop). Don't you feel all nice and toasty now?

You might notice I also hid the roof. This is because it would not appear in my render anyway and I wanted to save on system resources. I also hid all the non-visible geometry of my human models to save on even more resources.

Finally, once you have all your objects in place with all the materials set as you like in Reality, simply hit the Render Frame button to bring up LuxRender. Important Note: if your system has low RAM (less than 12 GB) you'll want to remove most of the displacement maps before you try to render, otherwise Lux may crash. This is because the current version of Lux will "subdivide" (a way to make objects look smoother by taking each face and dividing it into more faces automatically) your objects that have these maps, which causes it to eat up enormous amounts of RAM. For this scene, I needed over 6 GB just for Lux itself, even with most displacement maps deleted.

One great feature of Lux is the ability to change the entire tone of your image by adjusting the whitepoint. "Whitepoint" is a movable point that simply defines the lightest area in an image, causing all other areas to be adjusted accordingly. For outdoor scenes, I generally use D75 daylight or 9300. For this image I chose 9300.

Well, that concludes the tutorial. For more information on Reality please check out Pret-a-3D's website and for LuxRender you can see their wiki here,

Categories: Reality Tutorials (English)