Macha Posted July 31, 2009 Share Posted July 31, 2009 Here's some rocks I posted at the sidefx forums. I thought it would be a nice project to do a few more of these. It's very suitable to do in Houdini, so should be fun. I think the first thing to do would be to generate the basic shape. I'm wondering how to achieve this. Obsidian breaks like glass for example. The ones I have posted here look more like naturally occuring metals, or some kind of igneous extrusive with plenty of volatiles. So, how do I best achieve a chiselled surface? Lots of booleans? Quote Link to comment Share on other sites More sharing options...
altbighead Posted July 31, 2009 Share Posted July 31, 2009 I smoke some of it last night. Quote Link to comment Share on other sites More sharing options...
Macha Posted July 31, 2009 Author Share Posted July 31, 2009 Here's something a bit more felsic on the left with an ultramafic version on the right The basic shape was done by scattering concave objects around the surface and then shaping with a ray sop. At the moment I have crystals simply copy-stamped on the surface but that isn't very good because they would frequently be fractured more or less along the matrix cleavage. I want it more edgy and I need a way to use and blend different materials on the same surface. Can I drive a material parameter by simply typing an attribute in? Quote Link to comment Share on other sites More sharing options...
Macha Posted July 31, 2009 Author Share Posted July 31, 2009 Kind of a burnt pink granite with orthoclase megacrysts for which I used a cookie to define groups that I made with copy-stamped objects. I'll see if I can make something sedimentary next... Quote Link to comment Share on other sites More sharing options...
TheUsualAlex Posted July 31, 2009 Share Posted July 31, 2009 EDIT: my bad, I didn't read carefully. ;P Nice work tho. Quote Link to comment Share on other sites More sharing options...
Macha Posted July 31, 2009 Author Share Posted July 31, 2009 Imaginary oolithic limestone with crinoid fossils eroded by the sea... For the layered look I varied the density in a volume, scattered points, and copied deformed metaballs onto them, but it doesn't work well for small stratification patterns. Quote Link to comment Share on other sites More sharing options...
eetu Posted July 31, 2009 Share Posted July 31, 2009 Very nice and interesting stuff! eetu. Quote Link to comment Share on other sites More sharing options...
Magnus Pettersson Posted July 31, 2009 Share Posted July 31, 2009 looks very interesting, you got a very nice shading on it aswell =) Quote Link to comment Share on other sites More sharing options...
pclaes Posted July 31, 2009 Share Posted July 31, 2009 First of all, very nice work! Really like the volume based one! Can I drive a material parameter by simply typing an attribute in? You can't drive a material parameter by simply typing the attribute in one of the material parameter text boxes. You will have to create a parameter inside the shader that has the same name as the attribute you want to drive something with. It is fairly easy to do. Have a look at the "basic surface" material. In the parameters window it has a "Use point colors" checkbox. Now go inside of the basic material in shops, go in the vex surface shop, then go inside the "surface color" node (the big one with all the inputs). Inside of that one you can see how Cd is brought into the shader. The purple nodes are point attributes that can be used, you can make your own parameters, just make sure the spelling of the attribute is exactly the same and the type (float,vector,float[3]) is the same as well. In a very similar fashion you can create arbitrary output variables (the green nodes), that can be used for rendering those attributes as different layers in an .exr . Quote Link to comment Share on other sites More sharing options...
Macha Posted August 1, 2009 Author Share Posted August 1, 2009 Very nice and interesting stuff! eetu. Well, thanks to your volume_strata Quote Link to comment Share on other sites More sharing options...
Macha Posted August 3, 2009 Author Share Posted August 3, 2009 Some conglomerates. I tried to get more visible bedding structures but I still find it tricky to get finely detailed layers. Quote Link to comment Share on other sites More sharing options...
Macha Posted August 4, 2009 Author Share Posted August 4, 2009 Something metamorphic. Slate? The bedding is improving but I'd like the foliation to be more distinct. I really love Houdini for making rocks. Second to none, it's great fun! Quote Link to comment Share on other sites More sharing options...
Macha Posted August 4, 2009 Author Share Posted August 4, 2009 Breccia. I tried to get clasts with sharp, broken edges. Using the peak SOP was the key to this. Quote Link to comment Share on other sites More sharing options...
Jason Posted August 4, 2009 Share Posted August 4, 2009 These are amazing, Macha! And you get the prize for the the Most Random Thread on odforce Quote Link to comment Share on other sites More sharing options...
Macha Posted August 5, 2009 Author Share Posted August 5, 2009 (edited) My first mineral here. Good old pyrite. I want to try something translucent next. Is there a good SSS shader with displacement (that works in houdini 10) anywhere? Edited August 5, 2009 by Macha 2 Quote Link to comment Share on other sites More sharing options...
linhan4444 Posted August 6, 2009 Share Posted August 6, 2009 Very good Quote Link to comment Share on other sites More sharing options...
Macha Posted August 7, 2009 Author Share Posted August 7, 2009 (edited) Maybe salt crystals. I'd lick them if I knew they were. It's a lot harder to render than plain (but beautiful) rocks. I unchecked true displacement and used PBR rendering. There's a lot missing. No dispersion or birefringence yet, no pleochroism, nor have I found a good way to do internal cleavage and fracture structures. I did vary the IOR with an attribute though. That may be a way forward if I find out how to transfer attributes with pointclouds. Edited August 7, 2009 by Macha Quote Link to comment Share on other sites More sharing options...
pclaes Posted August 8, 2009 Share Posted August 8, 2009 If you get enough of these images, a museum might put them on the wall in high resolution! (I'm serious, you really should consider an exposition if you are into that). Quote Link to comment Share on other sites More sharing options...
Macha Posted August 11, 2009 Author Share Posted August 11, 2009 Imaginary crystals but I was inspired by calcite with its rhombohedral shape and weird internal planes. It took absolutely ages to render, perhaps because of caustics. It's certainly not the way to go. Quote Link to comment Share on other sites More sharing options...
Macha Posted August 11, 2009 Author Share Posted August 11, 2009 An extrusive, scoria type rock. Quote Link to comment Share on other sites More sharing options...
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