Any ideas how to achieve this with Vray? Or By geometry (more likely)

[mkhachfe]

I'm doing an animation involving a grain of sand , with the camera very close up. I have it looking pretty good so far, but what id really like to achieve are the INTERNAL cracks and fissures and opaque bits present in minerals. See the image below for reference. I guess to achieve what i want, i would have to model those bits somehow. Or is there a way of adding procedural displacement and glossiness that would THROUGH the mesh. I'm kind of stuck, so any ideas at all, would be very much appreciated.



Thanks!

[joconnell]

I'd probably use one of the breaking scripts like mb fracture to get your initial cracks, then select all of the internal faces for the broken sections and stick on a noise or displace modifier to bump them up a lot. you might have to even apply a different material to these faces with a more glossy refraction and spec, but the non smooth nature of the bumped faces will break up your refractions a lot to start with.

[mkhachfe]

Yeah, i figured it would be something like that. I fractured it with a script, then isolated the edges and put a more glossy material on them. That didnt quite work, so, im going to work on it some more tonight. Ill show you the results.

Im also playing with distributing with particles inside.

Ill keep you posted. Shame volumetric rendering never took off..thats really whats needed here i guess.

[simmsimaging]

I tested something like this for an older question on the forum about doing amber ( I think it was). I got some okay results by interpenetrating the object with a plane object and playing with the shape and material on that. Try translucent materials on that as a starting point. You can bend it around to create odd occlusions in the crystal, give it a shell for some thickness even. I think it worked out okay, but it was a while ago now.

b

[simmsimaging]

This is the thread. I didn't go too crazy with it since it wasn't my project, but the idea is workable I think. Check the post about 1/2 down the first page.

http://www.chaosgroup.com/forums/vbu...ighlight=amber

[joconnell]

Also back in the early days, people were trying to get a nice look for ice cubes that had a less see through, white centre, and they ended up doing it with three difference objects nested inside each other with progressively more glossy materials. Good luck with it!

[mkhachfe]

Thanks for all the suggestions guys. I got a pretty good result lat night. Im gonna work on it some more and then show what i got.

[mkhachfe]

Hi all, here are my results so far. I ended up building a foliage object (I forget which tree) and deleting the trunk, then adding a shell modifier, some noise, then running a script to randomly delete faces, then adding a few more modifiers and applying the same material as the big piece, but with different IOR. I think it worked out pretty weel, but not quite there yet. I want far more small detail. The displacement map on the front was a scratch map from cgtextures.com which was manipulated in PS.

Id love to hear any critiques. be hash, i can take it. I'm after 100% realism, which it isn't there yet.


Link:

http://imgur.com/a/5LtfX


Thanks again. Marc

[simmsimaging]

Definitely getting there. Did you try it with some refraction glossiness? That and possibly some SSS would probably get you nearly to your reference.


/b

[mkhachfe]

Another image, graded in After Effects

[joconnell]

You're definitely getting there - congrats!

[mkhachfe]

Not yet no. I was hoping to avoid that due to render times, so i may attempt to fake the refraction glossiness in after effects using a black and white separate SSS pass as the blur pass.

[mkhachfe]

Cheers dude, still needs work. By the way, i found this amazing site with incredible photos (and prices) of gorgeous minerals. have a look, some of the prices are just...wow. We are in the wrong field, put it that way.

http://www.irocks.com/vault.html?page=0

[mkhachfe]

One more image before i do a glossy refraction pass

[mkhachfe]

Here is a low res video if anyone is interested. Im going to keep refining it and do some nice big closeups

https://download.yousendit.com/M3BseVdwQk5sMHcxZXNUQw