[Sidefx-houdini-list] edge falloff for shader
jeff at sidefx.com
Mon Nov 13 18:30:13 EST 2017
You can use the Alpha Mix VOP which is equivalent to facing ratio as
well. It's the same thing as that referenced network.
Alpha roll sets the blending ration between parallel and perpendicular
input vectors compared to the current surface shading normal.
Alpha Para and Alpha Perp set the roll-off between parallel and
You can use the Alpha Mix VOP to calculate your facing ratio.
I do apologize for the VOP name but we were using this back in the mid
90's to do puffy cloudy stuff with particles rendered as spheres and you
mix Alpha based on the I eye ray and the surface normal. Alpha Para sets
the parallel strength and Alpha Perp sets strength perpendicular to the
surface normal. So I called it Alpha Mix VOP... In hindsight it should
be called Facing Ratio VOP... Please submit the RFE if you will to have
it renamed or duplicated.
See the attached file for a workup for an emissive object using a Geo
Light for efficiency. I presume you want to set up a glowy objecty
thingy based on your question.
On 2017-11-13 3:16 PM, Alvaro Castaneda wrote:
> you can calculate your own facing ratio using this method
> On Tue, Oct 31, 2017 at 2:36 PM, Gary Jaeger <gary at corestudio.com> wrote:
>> This one should be so easy. Coming from maya, with the facing ratio for
>> shaders. In my head it goes like: edge falloff, invert, pipe that into
>> opacity for a shader that has Emission on. So I get just a bit of emission
>> as the faces fall away from the camera. But I’ve been connecting things
>> left and right, but can’t get it to work.
>> Any help?
>> Gary Jaeger / 650.728.7957 direct / 415.518.1419 mobile
>> http://corestudio.com <http://corestudio.com/>
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
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