Category: Texture

Orientation Fields of a Rotating “Blobby” Object

Steven A. Cholewiak Leave a comment

In research I will be presenting in a few days at VSS (the Vision Sciences Society annual meeting), I will be demonstrating how we may use orientation flow fields of texture and shading when making perceptual judgments of 3D shape structure (see Fleming, Holtmann-Rice, & Bülthoff, 2011 for additional information). Since I find visualizations fun, I decided to use some spare CPU cycles overnight to visualize the orientation fields of a rotating blobby object.



The object on the left in the above video is a textured and shaded object with a small amount of specular reflection (lit using the Debvec Funston Beach at Sunset light probe). On the right, I’m illustrating the dominant orientations in the image, across the surface of the object.

Click through for some more visualizations.
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Effect of Environment Map Blur on Perceived Surface Properties

Steven A. Cholewiak Leave a comment

Here are a couple of quick demos, illustrating how blurring a cubic environmental map can lead to a change in the perceived roughness of the surface of 3D rendered objects.



I created a series of HDR cube maps using NVIDIA’s CubeMapGen (currently hosted on Google Code). Starting with the Debevec light probes, I applied a Gaussian blur with increasing kernel size (10°, 20°, 30°, 40°, and 50°), creating 6 cube maps (one for each blur). In the videos, the cube maps have increasing blur from left-to-right, top-to-bottom. Note that I did not tone-map or account for changes in overall exposure (so the specular reflections can appear blown-out, especially for the higher blurs). After the break, you can see the effect using different light probes (and different shapes).

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