6th Century Stone…

Here’s a proper blog post for this month 😀

A year or two back, I visited the hillside ruins of a 6th century monastery in Cooley, on the Inishowen peninsula in Donegal, Ireland. It’s an overgrown graveyard now, and among the ruins there is a well-preserved 10 foot high cross and a few free-standing church walls. Perhaps most notable is a “Skull House”, fashioned after the Beehive huts of Ireland’s early monks, reported to contain the remains of saints, and up until recently human bones could be seen through a small aperture in the wall.  I respectfully set about making a scan of the Skull House, but my fully charged phone mysteriously died and wouldn’t turn back on. Back to the car to charge it and I manged to switch it back on, but the battery level had dropped by half, weird! There was enough charge left to take the photos I needed, hampered only by height and foliage on the sloped roof. Here’s how it looked:

As with every 3D scan like this, the textures are bound to the geometry created, but I wanted to create a material from the Skull House that I could use on any model, so to be practical it would need to tile and I’d also have to repair the occluded areas, mainly the grass and mossy clumps. As a starting point, I rendered off the raw geometry in 3DSMax as diffuse, normals, AO and z-depth (for height) for each side and combined each wall into a single texture, then ran it through Artomatix to mutate the missing areas. It became clear that I’d have to paint a structure guide to help the mutation process, as it seemed to produce weird melded stones rather than fully separated stones. A structure guide basically means painting an outline for each brick, which in this case was time-consuming and problematic due to the variation in stone size and years of moss growth. To fix this, I displaced a plane with the seamless height map from Artomatix in Mudbox and sculpted into the gaps while sharpening up stone edges. This broke the tiling from Artomatix but I was otherwise happy with the look. I also worked over the grassy clumps and overhangs in 3DSMax using both Max’s hair and fur modifier and some hand modelled grass blades. Some shadow removal and adjustments to the albedo and an eyeballed roughness map in Photoshop and here’s what I came up with:

The next part, was to test against some proper geometry, which would have be low poly but with even topology, as I would be using displacement and tessellation and with as few sharp corners as possible to avoid self-penetration when vertices were displaced. UVs are important too, orientation and continuity ensure that the grass and moss are properly placed. This is some quick low poly geometry I created that approximates the shape of the original Skull House

Here is the same scene with the tiling material applied, click on the image for higher res. The ground material in these shots was created with Quixel Mixer, based on Megascans

With daytime lighting 

So even though the texturing is now less specific, with far less moss and grass to see, it works around chamfered corners and on different models as long as the UVs are carefully laid out, every break in continuity can cause a model to crack along seams.

I couldn’t help but be reminded of the stonework of the “Beehive hut” monastery on the Skelligs, also from the 6th century and location for Luke’s home on Ahch-To in the new Star Wars movies. For a further test I used a hemisphere primitive, cut a shape for the door and lintel and extruded a small piece at the side, again avoiding splits in the UV islands where possible. The more detailed geometry in the background below is just for decoration. Here is the scene without textures:

Here it is with the material applied:

And with a little more atmosphere, inspired by the movie Prometheus:

In motion with some rain effects added in After Effects:

 

Bonus content: I also scanned this at Cooley Graveyard:

 

 

 

 

 

 

 

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~ by petemcnally on July 25, 2018.

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