Utilizing Mixer in Terrain Production

Juan Paulo Mardónez gave a talk on natural terrain production with Quixel Mixer and other tools, shared the heightmap creation process and gave some tips for hiding the tiling marks.

Introduction

I’m Juan Paulo Mardónez, from Chile. I’ve been working in 3D since 1994. I’m the founder and CEO of Leyenda, an animation and VFX studio located in Santiago, Chile. We’ve been working in advertising (TV commercials) since 2001. I’m an atypical CEO though… I work and direct within the trenches with my team, so I’m up to date with pretty much every aspect of the 3D pipeline and also, since I’ve done everything you can imagine (modeling, texturing, hair grooming, rigging, lighting, animating, camera layout, compositing. and directing), I understand very well the struggle each artist has to deal with, so my role is to help and support them every day. I also do experimental work and try new ideas, like the ones we are talking about here, and then I share them with my team.

Here’s an example of our work (I was responsible for modeling, scene setup, fur grooming, lighting, and compositing supervision. Used Megascans here).

Tools Used

There’re so many 3D tools these days, but I prefer to work with just a few of them: Maya, ZBrush, Mixer, World Creator 2, and Gaea. I think the combination of these tools give you incredible power and creative freedom. With WC2 + Gaea + Mixer, you can create an interesting image without any need to go and render outside Mixer. This allows me to make one or two Mixer sketches a day, at the same time I’m doing 3D with my team and managing my company. So, this tool combo allows me to express very fast whatever I want to share with the community. Oh, I forgot one, maybe the most important one: a pencil and paper! I’m sketching ideas all day!

Experiments with Mixer in Landscapes

I experimented with both aerial photography, macro photography, and everything in between. Once you fly a drone over a cliff at different altitudes you start understanding the hierarchy of forms and when small details became irrelevant. The scale is something we understand according to our human point of view, so if something is off, we spot it quickly.

I started playing with Gaea in the early phases of software development, and at the same time, I discovered World Creator 2. I’ve been playing with these two for months, but Mixer was not really a part of the equation, mainly because of me having hardware limitations, I was not able to work fast enough with Mixer until I upgraded the network, the systems and my graphics card. So, once I had all tuned up, I tried Mixer again and It was flawless working at 4k in real-time over the network. Then, I decided to try the results of the terrain generators with Mixer. It’s funny, but for me, this was the first thing I wanted to do with Mixer.

Regarding my goals here, they are simple: push Mixer to the maximum to prove that I can use it for ultra-high-altitude images, microscopic images and everything in between. For this approach I’m using Mixer’s limitations as challenges, I’m not going into Maya to do photorealistic Arnold renders. So, nothing but the Mixer viewport. After I master this, I will go further with camera moves and other gimmicks.

Heightmap

I have 3 ways of approaching the heightmap creation:

• Direct modeling in Maya or Zbrush to generate a predictable form. Then create a grabdoc in ZBrush to get a 16-bit depth alpha. I can work directly with this in Mixer.

• Terrain generation in World Creator 2: This tool is GPU based, so creating terrains and shapes in realtime is incredibly fast. It has a lot of interesting filters you can mix to get realistic or fantastic shapes. It also exports 32-bit images really fast. From there I get the heightmaps into Mixer.
• Terrain generation with Quadspinner’s GAEA. This is a node based terrain generation tool. It feels a bit intimidating at first, but once you understand the logic behind it you can unleash incredible power with its multiple creation and edition tools. Exporting is a bit slower than WC2, but the results are unparalleled.

After I import the Heightmap into Mixer I drop a few RGB solids with curvature masks to find depth sectors. Then I import Megascans surfaces and copy the previous masks and tweak until I feel it’s done. The other limitation I use is lightning, as per now Mixer has limited Probes, but you can rotate and increase light with them. Also, I spend some time searching for an interesting angle to take the shot.

Natural Terrain Production

I study a lot of references, from reality or fantasy, to get a grasp on the scale, color, and light. My objective is to make a good composition with the least number of elements and resources. This is where Megascans shine, as it saves you tons of time.

Regarding terrains, the variation on the heightmap depth is key to tiling avoidance, I mean, every depth feature could have its own material properties. So, to break tiling you need to break surface continuity, to break surface continuity you can use depth. Everything can be separated and blended with curvature masks and moving up or down the layer depth threshold.

Hiding Tiling Marks

Sometimes the scan could be used only with 1 or 2 tiles, even for landscapes. If you tile a scan a lot and look from above you will see tiling no matter what. The key is the height variation and changing the direction of midsized details of the base heightmap. If the heightmap has enough depth information you will be able to squeeze way better the blending modes in Mixer, using the curvature mask of course. The other key idea here is the following; I think of Mixer as a storytelling tool, so for me, the image I’m creating should self-explain how the forces of nature created it. For instance, dirt and rock were eroded by a river of lava decades ago, now water fills the spaces and leaves humidity and moss, and finally, I see a small amount of water at the bottom. You need to feel the geological process looking at the image.

I think the best way to approach this without cluttering the surface is creating a nice heightmap and then adding colors just with solids. Once the image looks promising with flat colors add Megascans surfaces one at a time, giving them a function in the scene, IMHO less is more.

Mixer’s Powers

Before, I agreed with an opinion that such an approach could work only for small landscapes, but now I’m sure Mixer can handle everything, from microscopic to wide aerial shots. Mixer is not restricted to Megascans surfaces. Mixer’s power is precisely blending depth, whatever scale you are using. For example, if you create satmaps (colors patterns) in GAEA you can mix them in Mixer and get very cool results… I mean, don’t feel forced to drop a scan every time, you can work creatively with solids, masks and blending because the further you are from the surface the less detail you will be able to see.

Juan Paulo Mardónez, CEO at Leyenda

Interview conducted by Kirill Tokarev