A 3DS Max tutorial that will help you create mental ray clay renderings in a couple of minutes. Clay rendering is a very common technique that most of us use when showcasing unfinished or untextured models.

Preview

1/4 – the scene

Go to and download our 19th century church model. The zip includes an fbx file that is completely untextured.

Fire up max, click the import button and browse to the FBX file you’ve downloaded previously:

Create a large plane beneath the church so we can see some cast shadows.

2/4 Render setup and Lights

We need to enable mental ray. Press F10 or go to the Rendering/ Render Setup menu. Scroll down the common tab and roll-out the assign renderer panel. Click the production button and assign the mental ray renderer

Any good clay rendering needs some form of easy to implement, good looking lights. Go to the Systems {} tab and create a Daylight system. Just click yes on whatever pops up.

With the Daylight system still selected, click the modify tab {}. We’re going to tie it in to mental ray. Set the Sunlight to mr Sun and the Skylight to mr Sky

3/4 The material

The one thing that is an absolute must for clay renderings is the Ambient / Reflective occlusion map. Open up the Material Editor {} by pressing the “m” key and select an empty slot. Click the diffuse map check-box and assign an Ambient / Reflective occlusion map.

While we’re here, set the Samples to 48 (less noise), the spread (the spread of the occlusion soft shadow) to 0.9 and the distance to about 5. Apply the material {} to both the objects in the scene.

You can render it now. Remember that material noise can also be generated by the Ambient / Reflective occlusion sample settings.

4/4 The tweaks

To some, this step could be unnecessary but lets make it look just a bit better by getting rid of the jagged edges. Open up the Render Setup {} window (“F10“) and go to the Renderer tab. Set the Samples per pixel to 4 and 4

To get an even better result we’re going to increase the Final Gather Settings. Open up the Render Setup window (“F10“) and go to the Indirect Illumination tab. Set the FG precision to low or medium (this will reduce any grainy shading) and set the Diffuse Bounces to 2 (maximum light bounces)

Pick a nice angle and render the scene.

That’s all folks

To sum things up:

Prerequisites:
> Good lighting – daylight system
> Ambient occlusion map – more samples, less grain, spread and distance is based on object size

Rendering
> Final Gather – Higher precision reduces noise, diffuse bounces make for a better lit, slightly more realistic rendering
> Samples per pixel – Higher values, less jagged edges.