Pete Mc Nally's Blog

Happy New Year – first post of 2012! Another lunchtime challenge, this time to see if I could make some decent looking rocky crags in an hour using only basic geometry and procedural textures in 3DSMax. Organic rocks can be very difficult to get right, scale and detail can often be difficult to eyeball and procedural textures must be carefully nested to remove the obvious patterns of cellular noise. I started by extruding a wavy spline, cloning/offsetting the resulting mesh and then attaching them as editable polys, using the bridge feature to patch up the hole and connecting edges where appropriate to help regularise the topology for displacement.

I then instanced the mesh a few times, allowing it to overlap and not being too careful about placement. I rotated an instance and used it as a ground plane, again intersecting the vertical base meshes.

At this point I composed the image and locked off the camera. For lighting, I added a Mental Ray daylight system and turned on Final Gather using 2 bounces at draft settings. After playing with the sun position I ended up with this:

I used 3DSMax’s displacement modifier rather than Mental Ray’s excellent shader displacement for speed purposes – I needed to be able to see the results in the viewport rather than endlessly rendering and tweaking. I wanted the segmented bumpiness of a cellular procedural map but I knew this would look unnatural so I broke it up in a composite map by multiplying a smoke procedural map over it and playing with the size. This was applied using planar mapping.

This roughened up the base mesh pretty nicely:

Adding a turbosmooth below the displacement modifier to get some extra detail (one of the benefits of using procedural textures) gave me this:

Lastly as time was running out I needed a quick way of adding some variety to the diffuse colour, which I thought should be a canyon red. I tried some fresnel effects on the dry rock but none gave the effect I wanted, so I opted for an arch & design material with a Mental Ray landscape map for the diffuse. This allowed me to choose a reddish colour for the slopes and a lighter brownish-yellow for flatter areas, which should look dusty or sandy where sediment would collect. I then added a procedural smoke bump map for fine detail not captured by the displacement, leaving me with this:

The image was a bit washed out so I took it into Photoshop for some colour correction and enhanced the sky with a hint of cloud and an aeroplane contrail. I faked a little depth of field in the left bottom corner and added some noise. Here is the final image.

~ by petemcnally on January 12, 2012.

Posted in Personal Work
Tags: 3dsmax, cliff, colour correction, composite, displacement, exterior, landscape, Mental Ray, photoshop, procedural, rocks