6/8: Homogeneous Volume Attempt


Attempt at a single scatter homogenous volume render. The dragon looks a lot better now! Looking closely, you can see the scatter of the light inside the object and it is starting to get a bit closer to jade. If you look at the small parts, it looks more dense and lesss light is being let through which will require some tweaking. https://graphics.pixar.com/library/ProductionVolumeRendering/paper.pdf




Updated coloring from https://books.google.com/books?id=V8NwDwAAQBAJ&pg=PT241&lpg=PT241&dq=jade+material+color+rgb&source=bl&ots=Tnv3iH648v&sig=ACfU3U1W4tqYCJXW5s_bJOSs0wm3vkFvdw&hl=en&sa=X&ved=2ahUKEwjd2_71hvLpAhWlJzQIHcQ0ALAQ6AEwF3oECAoQAQ#v=onepage&q&f=false section 7.3 which actually dives into the jade material instead

Values being used are close, but it felt a bit too white so I slightly tweaked it
diffuse 0.4 0.95 0.60
shininess 12.8
ambient 0.135 0.2225 0.1575
specular 0.3162 0.3162 0.3162





Reduced scatter distance by factor of two. Less glassy feel but the weird shading effects are a lot more noticeable now which causes the skin to look like it folds on itself. The head is also still too reflective. It feels like the jade is not being processed correctly(potentially because it has multiple intersections with the jade and enters and then exits before entering again causing issues.




The tip of the tail is the only part looking pretty close to what is expected.
The current drawback of single subsurface scattering is the result gets essentially flipped with what we are expecting. The larger volumes scatter the same amount as the shorter ones, just the scatter distance is different. This makes it so that it seems like thin edges are the densest parts while the large areas are the most translucent.





Comments

Post a Comment

Popular posts from this blog

6/7: Time for a reset

Image
Time to go back to our basic code with nee + rr. We were initially checking for jade as a completely separate material similar to how we processed lights. This approach is probably not correct which caused the lighting issues because light should still be integrated as normal, but if we hit jade we do different code. So now we need to reattempt integration but put it inside where we calculate direct lighting + indirect lighting. We've also cleaned up the code as it was fairly messy what did what and now everything is more clear. Goal: Achieve basic refracting for this dragon Implementing:  https://www.cs.rpi.edu/~cutler/classes/advancedgraphics/S10/final_projects/turnbull.pdf Reason we do this is because the basic of subsurface scattering is deciding between refracting and reflecting inside of the object. If we can figure out how to nail refractance, combining it with the preexisting reflectance code shouldn't be too bad. Well looking at it, it's actually not that bad right...
Read more

6/9 Final Results

Image
Here are the final results for our attempt at subsurface scattering. We managed to get single-scatter events to work (this image was referenced in a previous post). The main issue, in the end, was attempting to integrate into multi-scatter events. The way direct lighting processed a specular surface caused issues in which it would create a glossy texture and we could somewhat render out the individual components of the scatter and the diffuse, but combining the two made it look like just a diffuse with more specularity. We believed that this image above best demonstrates subsurface scattering. Despite not achieving the jade effects we aimed for, we managed to successfully process lighting within an object with single scatter events. For a reference to our initial images, this is what we started with: Finally, here is what we aimed to achieve:  Through this project, we've learned a lot about the physical properties of objects and how subsurface scattering works on a fundamental leve...
Read more