[Sidefx-houdini-list] Microbevel?

Erkan Özgür Yılmaz eoyilmaz at gmail.com
Tue Aug 31 17:43:45 EDT 2010

I found the original patent documentation from Hakan Anderson (the famous
mentalray shader developer)...

I'm still reading and trying to harvest some information about the shader.
As far as I see it's like that:

1- find a tangent vector which is perpendicular to the shading normal (it is
kinda easy, have done it before a couple of times)
2- use the tangent vector and start rotating it around the normal
3- for 6 equal angled or evenly spaced directions try to search for other
surface points within a distance R (bevel radius, and the search can be done
with a rayHit vop)
4- if you find a point and it is within R, then calculate a weight
5- multiply the weight and the shading normal of that point and get a
weighted normal (the formula of the weight is given in the patent)
6- sum up all the 6 found weighted normals
7- add them to the original N, then normalize N

this is what I get from the patent documentation...

here is the link to the patent site ( it is an OCR text, if you are
interested try to download the pdf version):

I'm trying what I explained before, but what I get is irrelevant. I think my
problem is about spaces (object, current, world etc.)

will inform if I get anything


E.Ozgur Yilmaz
Lead Technical Director

On Tue, Aug 31, 2010 at 8:20 PM, Robert Kelly <isstuff at gmail.com> wrote:

> There was a plugin i used for 3ds max years ago that was made by the
> vray guys that made a bump map at the corners of polys to simulate a
> small bevel... i guess this could be built in Houdini and applied to
> the displacement
> http://3d-studio.org/A.LIST-Advanced.3ds.max.5-Mo/6553/DDU0096.html
> On 31 August 2010 09:10, Simon Barrick <simon at primalpictures.com> wrote:
> > I do have a version that works in H10, no idea if it's the same as the
> maya one. I can't add attachments here so mail me off list if you'd like it.
> >
> >
> > -----Original Message-----
> > From: sidefx-houdini-list-bounces at sidefx.com [mailto:
> sidefx-houdini-list-bounces at sidefx.com] On Behalf Of Erkan Özgür Yilmaz
> > Sent: 31 August 2010 10:27
> > To: sidefx-houdini-list at sidefx.com
> > Subject: [Sidefx-houdini-list] Microbevel?
> >
> > Do anyone has an idea about how to create the "round corner" (a popular
> mentalray bump shader I use in maya) kind of effect in houdini. It is kinda
> smoothing the normals in rendertime around the corners/sharp edges in the
> model.
> >
> > As the subject suggests I found a vop which does that exactly, but it
> seems that it is only working in houdini 8
> >
> > Erkan Ozgur Yilmaz
> > Lead Tecnical Director
> > eoyilmaz.blogspot.com
> > www.ozgurfx.com
> >
> > Sent from my Galaxy S
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