My last post showed that one of the props I’ve built for the USCSS Conrad build was a Facehugger. I guess that means the cat’s out of the bag about the whole thing being an Alien tribute.
Making the Facehugger was a little out of my comfort zone but ended up being a lot less trouble than I expected for such a complex organic shape. In this post I’m going to run through the steps I took to create the mesh and textures. A lot of this is going to be specific to the tools I use, like Lightwave, but I’m going to talk in general terms as much as possible so that it’s applicable to whatever tools you’re using (hint: not Lightwave – I think I’m the only one left using it for SL!).
Building the Mesh
The Facehugger has a symmetrical structure; on each side there are four digitals (or “legs”, if you’re not a synthetic – I’m looking at you, Ash), a breathing sac and half of the tail. That gives us six things per side, so I began with a short twelve sided cylinder. I pulled the vertices at the back out to give it a more elliptical shape, and wider faces to serve as the roots of the breathing sacs.
The first four polygons on each side I extended out into the legs. At this point I’m just roughing things out so I just extended the edges using Lightwave’s bevel tool which allows you to extend out a polygon along its normal and scale the result at the same time. Three applications got me legs with two very basic knuckles on each.
I similarly beveled out the extended polys behind the legs to form the breathing sacs. Another bevel on the top rounded out the back of the creature a little.
Now that I had the shape of the creature roughed out I started working with it as a subdivision surface. Hitting Tab in Lightwave toggles between mesh and subdiv, so I was switching back and forth, refining the mesh to create a more detailed subdiv surface.
I added more detail on the bottom of the creature, beveling it into a hollow then scaling the vertices inward and beveling again to create the hollow proboscis.
This looked like it was going in the right direction so I extended the tail, finalising the overall shape of the thing.
Next up it was time to refine the detail of the Facehugger. This involved a lot of switching in and out of subdiv mode, dragging vertices around and scratching my head while looking at reference material.
The biggest change was the rebuild of the legs. They needed to have knuckles rather than just be straight. Everything after the end of the first poly was amputated and rebuilt with boxy joints that would pull the subdiv surface out into the knuckles I needed. This left the base mesh looking a little lumpy,
but it worked a treat for the subdiv surface.
At this point I was happy enough with the basic shape of the subdiv surface so I froze it into a mesh (Ctrl+D, in case you were wondering how Lightwave rolls) and looked to the UV maps.
There’s just no good way to unwrap a mesh this convoluted. You can break the thing up into dozens of UV islands that make efficient use of the map space at the expense of making the thing practically impossible to work with. In the end I elected to split the mesh into top and bottom halves, unwrap each separately and then plonk them down next to each other. This ends up with a fair amount of dead unused space on the UV map but it’s a map you can work with in 2D painting packages quite easily. Everything’s swings and roundabouts.
So, now things need more detail. Time to break out Zbrush!
I exported the UV mapped mesh as a Wavefront OBJ file (I know Lightwave has GoZ now, but it just doesn’t work in a useful way) and imported it into Zbrush as a new tool. There’s not a lot interesting to say about the Zbrush process – if you know Zbrush then you can imagine it all already. If you don’t, well, nothing I can say will make it clear.
I moved from mouse to the Wacom tablet and added detail to the model in Zbrush, ending up with a super-high poly model with ribbed flesh, extended knuckles and all kinds of lightly nauseating detail around the proboscis on the underside. I could probably have accomplished the same results in Sculptris but I was feeling crash-averse that day and opted for Zbrush.
I exported the high poly model from Zbrush and used that with the original mesh to create a normal map in xNormal. Both models were in Wavefront OBJ format which xNormal likes well enough. A little fiddling with the settings got me a clean normal map.
I fed this normal map to Knald and it obligingly generated me height, concavity, convexity and ambient occlusion maps from it.
There’s a lot of useful information in these different maps – layering them together in a 2D package like GIMP with different blend modes can create some interesting effects. I played with this for a while until I got something I was happy with, then painted in more detail like the red, fleshy underside around the proboscis. This comprised several layers: colour, highlights, blue veins, red veins, more highlights. I added some more colour with a textured brush over the top of everything to produce a diffuse map for the model that, I think, worked pretty well. I wasn’t too precise with things since a little randomness enhances the overall organic feel of the model, I think.
I also used a similar process to create a specular map that gave some low shine over the creature’s body and a slippery gloss around the fleshy underside.
The final stage was to use Lightwave to arrange the low poly model in several different poses as required for the overall build – curled up and dead, flat out and dead (and more, perhaps not so dead 😉 ).
Uploaded to SL this looks just as good as I’d hoped when I began the build. The land impact is relatively high at seven, but with a shape this complex I was never going to get away with much less while preserving the silhouette – the Conrad build has a heavy emphasis on lighting and shadows so the silhouette of the model was quite important to me.