Grasshopper

algorithmic modeling for Rhino

Twirl Sphere

No rendering, no post-processing, images are grasshopper previews.

Animation in comments.

Ive been playing with previews a little bit in past, but seeing Andrews almost ambient occlusion shading. http://www.grasshopper3d.com/video/heads-up-display-with-human
I thought i would try lighting effects. This just works on mesh rays to the light source, determining whether they should be light or dark. One issue here is that the shadows should be sharper where its closer, instead of blurrier.

www.tyrertecture.com

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Comment by Nick Tyrer on March 25, 2014 at 8:42am

Comment by Daniel Piker on March 25, 2014 at 4:13am

Nick - You're right, it could be done by just taking a line from a point on the plane to the top of the sphere and intersecting it to get the corresponding point on the sphere.

Comment by Nick Tyrer on March 25, 2014 at 3:41am

Vicente, i'm not sure i quite follow. I remember your post about AO, it was very helpful. but i haven't tried to recreate that, i had just never considered using a background mesh to enhance the effects that i was doing on the main object.

Daniel, i had not seen those particular stereographic sculptures before, its an interesting concept, and i may be mistaken, but should be alarmingly simple to create. Did you have a blog post about it a few years ago? 

Comment by Vicente Soler on March 24, 2014 at 4:55pm

As Andrew suggested, in this animation http://www.grasshopper3d.com/video/more-dla first I had proper ambient occlusion by intersecting several rays per vertex in random directions (as I did here, also in one of your images) but then realized a single ray plus mesh blur looked good enough and was much much faster (you commented on the definition, you must have missed the AO part).

Comment by Daniel Piker on March 24, 2014 at 4:20pm

Nice!

Have you seen these stereographic projection sculptures by Henry Segerman:

Comment by Nick Tyrer on March 24, 2014 at 11:16am

damn it, i was gonna try and work that out myself, haha thanks man, much simpler method..

Comment by Andrew Heumann on March 24, 2014 at 10:47am

on second thought you could also just use "blur mesh" and then do a weighted interpolation between the blurred mesh colors and the sharp mesh colors

Comment by Nick Tyrer on March 24, 2014 at 10:21am

Haha just looking at this i realised there is a glaring mistake, the mesh ray was sampling both sides of the mesh, so giving me double shadows.

New version:

Not 100% sure how to apply that blur/noise Andrew. Let me think on it, and i may come back to you with questions if i fail

Comment by Andrew Heumann on March 24, 2014 at 9:23am
You could force the blurring a bit toward the edges by adding a little random noise to the vectors weighed by distance from the object

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