[Sidefx-houdini-list] point versus vertex textures ...

Georg Duemlein, Dipl.-Des. info at preset.de
Thu Feb 8 01:59:59 EST 2007


First I have to say hello as I am new to this list.
My name Georg and I am starting to get into Houdini.

:( I after rereading I see I miss understood the question ...
So this is more about Vertex Colors than Vertex Textures.
But the topic title is rather non-ambiguous :)

-- ---

It is funny - this is the first topic on the list I participate as
Vertex Colors just got on my radar through Houdini.
I am a longtime max user and I always pushed them into the "gaming 
stuff" corner.

After watching the video tutorials from Buzz and Garman I got the 
impression that Houdini is a "native vertex dyer" - as long as I don't 
apply a SHOP everything is done by coloring points.
(I know this is not true, but it was the first impression.)
This videos and a posting at cgtalk showed me the use for vertex colors:

Using a "vertex color shader" I can use a single material/shader for a 
group of objects sharing the same properties but being different in one 
attribute which is defined by the vertex color.

Example: a console of interface buttons: the shader defines the overall 
look (of course they look all like osx buttons ;) - an animatable 
attribute changes the vertex color of each button depending on its state 
(unused, pressed, warning, error ...)
That way the content (color) is separated from style (shader).

I don't know if this is a legitimate approach in Houdini.
I got the impression MAX doesn't really like it.
I am currently writing a tutorial/chapter about this and like to compare 
the workflow approach as soon as I understand it in Houdini.

-- ---

Georg






Darran Edmundson wrote:
> 
> A colleague familiar with other tools asked by about the following in 
> houdini::
> 
> "I want to create a textured box with smooth normals but with 'faces 
> painted' i.e., different UVs at each vertex which are not continuous 
> over adjacent faces. The typical textured box then. In other tools this 
> can often be implemented as 8 points but with multiple UVs at each point 
> (so the vertices generated have to be duplicated). Given what I've seen 
> when using the 'Facet' operator, I'm wondering whether I need to do this 
> in Houdini or not. But I don't know the typical methods of generating 
> UVs like this - I've had a quick go but haven't spent a lot of time on 
> it yet."
> 
> His question made be realize that I've never explored vertex texturing 
> in Houdini.  My approach would be to use a Facet SOP with unique points 
> followed by a UVTexture SOP with faces and point texturing.  In this 
> case (where he wants smooth normals anyway), it is obviously wasteful in 
> terms of replicating points.  Plus I'd need to massage the cusped 
> normals at coincident points on differing faces to be the same.
> 
> When do you use vertex texturing?
> 
> Cheers,
> Darran.
> 

-- 
Dipl.-Des. Georg Dümlein

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