gaurav Posted July 3, 2014 Share Posted July 3, 2014 Hi Guys, I am intersted in finding out how much of illuminance (that is integrated luminance over the hemisphere) is scaled on a point being shaded by a given BRDF function. Is it possible to grab this value at shading time. I find terminology /units of photomery and radiometry rather confusing in the begining and just wanted check my understanding. Thanks, -Gaurav Quote Link to comment Share on other sites More sharing options...
eetu Posted July 3, 2014 Share Posted July 3, 2014 If I understand you correctly, Albedo SHOP is what you are looking for: http://www.sidefx.com/docs/houdini13.0/nodes/vop/albedo Quote Link to comment Share on other sites More sharing options...
gaurav Posted July 6, 2014 Author Share Posted July 6, 2014 Thanks eetu, seems default surface model vop has it (albido- [diffuse+glossy]) exported as "direct_reflectivity".Which by no surpirse is the sum of diffuse + specular intensities parms.But if i get it right, the BRDF depends on incoming and outgoing direction and gives the relative distribution of scattered and reflected light over all outgoing directions. Now on a humble [diffuse and reflective] sphere i would expect to see varying values returned by specifc BRDF function by which all the incoming radiance (direct + indirect)to a point on its surface are scaled. which i dont find in the direct_reflectivity aov. I am new to these highfalutin terms to extent of not even being sure what i am asking makes sense with that said here is my second question : 2. Does Physically Based Diffuse vop implements standard lambertian model ? Thanks, -Gaurav Quote Link to comment Share on other sites More sharing options...
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