[Sidefx-houdini-list] Copy SOP

Chandra Maharzan chandra at digital.com.np
Fri Mar 7 08:58:46 EST 2008

Hi Phil,

First of all, I would like to thank you very much for taking time to
actually do this and explain it to me. Very much appreciated.

I tried it and it looks wonderful. I am not sure why you actually created
the Sphere. Is there a specific reason? I could only guess because we can
use sweep and copy SOP if we need to change the tile orientation

I will try to integrate this in my project and see how it comes out there.

Thanks again,


-----Original Message-----
From: sidefx-houdini-list-bounces at sidefx.com
[mailto:sidefx-houdini-list-bounces at sidefx.com] On Behalf Of Phil Spicer
Sent: Friday, March 07, 2008 3:41 PM
To: sidefx-houdini-list at sidefx.com
Subject: Re: [Sidefx-houdini-list] Copy SOP

Hi Chandra,

You can get it to work if you implement Rangi's suggested sweep copy

1. Create your curve

I used a Circle SOP set to Polygon - radius 5,1 - Divisions 15 - Arc
Type Open Arc - Arc Angles 40,140

2. Resample it using a Resample SOP (uncheck Max Seg Length, check Max
Segs - Segments 10)

3. Create a Sphere SOP (Primitive) and append to it a Point SOP (Add
Normals 0,0,1 - Add Up Vector 0,1,0).

4. Using a Sweep SOP, sweep the output of the Point SOP onto the
re-sampled curve. Set the Roll parameter of the Sweep SOP to -11 to
reorient the axis (I think this is because of using an open arc circle
as the sweep curve)

5. Create a Box SOP and flatten it in the Y Axis to create a tile (size
1,0.1,1), append to it a Transform Axis SOP (Direction 1,0,0 - Rotation

6. Using a Copy SOP, copy the tile onto the output of the Sweep SOP.

You can then adjust the rotation of the Transform Axis SOP to help it
match your curve. If your curve has flat and rounded areas you will need
to use Copy SOP stamping to control the rotation on a per tile basis.

It also seems dependant upon your initial curve. I got overlapping  tiles
going up a spiral without having to use the Sweep / Copy technique.

Anyway I hope this helps... welcome to Houdini.

Kind regards,


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