Polyextrude Distance Scale

[Homer0]

Hi all, i've purchased the Helloluxx training "Tea and Cookies", and i've encountered a problem with the Polyextrude, since the course was made in Houdini 13, when you could use local variables in the parameters.

Problem is, if i try to drive the extrusion distance based on the object color, it works only if the "Divide into" is set to Individual components; which in my case is not usefull (i'm doing a tea spoon, trying to give it an extrusion higher in the handle than in the tip).

Any workaround for this issue?

Thanks ^^

 

[Sepu]

Here it works the same way.

extrusion.hipnc

[Homer0]

unfortunately it doesn't work. As i said, it works good when the geometry Y is located on Y=0. If you have a geometry with some point above 0 and others below; this methos flattens everything to Y=0 before it starts.

The solution would be to move the Point position along their normal, adding the value to the existing position; but sadly i don't know how to do such a thing.

 

Here's the scene:

Spoon.hipnc

Edited December 17, 2016 by Homer0

[Sepu]

I see... then use 

@P.y += @N.y * @Cd.r;

[Homer0]

Yep, now it works. Another solution that a user suggested on another forum was to use Displace Along Normal vop, tried that and basically it's the same ^^

Btw, i'm trying to undestard the VEX stuff, but i couldn't find a list of parameter to use. I searched in the help with no luck. Is there somewhere a list with all the parameters like @P , @N, @Cd, etc.?

Also i noticed, in your expression, that the + makes all the difference, correct me if i'm wrong:

@P.y = @N.y * @Cd.r;  = the Y position is egual to the Y normal multiplied for the red color channel

@P.y += @N.y * @Cd.r;  = the Y position is egual to the Y normal multiplied for the red color channel, added to the current Y position

[Sepu]

Hi, Yes your assumptions are correct. You could also do it in VOPs with the displace along the normal. 

which basically is what I did but just with VEX, sometimes is just quicker to write some code than going to VOPs.

@P.y = @P.y + @N.y * @Cd.r;

the += is just a shorthand operator

Here are some site that might help you as well.

https://www.sidefx.com/docs/houdini15.5/vex/snippets

https://www.sidefx.com/docs/houdini15.5/vex/lang

Edited December 18, 2016 by Sepu

[Homer0]

I see. Thanks a lot for all the info ^^