Houdini tutorial | Building the orientation matrix for local rotation

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Olivier Jeannel

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Mar 9, 2017, 8:40:09 AM3/9/17
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I made a little tutorial on how to get local rotation when working in houdini.

Build an orientation matrix
Rotate using the orient attribute before the copy sop
Rotate objects after the copy sop.

And it's all VOP !

Jonathan Moore

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Mar 9, 2017, 9:23:09 AM3/9/17
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Nice clear explanation Oliver.

Jonathan Moore

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Mar 9, 2017, 12:49:36 PM3/9/17
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Just a thought with regards to the creation of the ‘up vector’ via the Point SOP. This has been deprecated in H16 and in its place you would use the Attribute Expression SOP (you can still call it on the tab menu via Point…) as this is multithreaded. The workflows a little different but just a simple.

 

 

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Olivier Jeannel
Sent: 09 March 2017 13:40
To: soft...@listproc.autodesk.com
Subject: Houdini tutorial | Building the orientation matrix for local rotation

 

I made a little tutorial on how to get local rotation when working in houdini.

image001.png

Tim Bolland

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Mar 10, 2017, 3:43:19 AM3/10/17
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Thank you Olivier! 


From: softimag...@listproc.autodesk.com <softimag...@listproc.autodesk.com> on behalf of Olivier Jeannel <facial...@gmail.com>
Sent: 09 March 2017 13:39

To: soft...@listproc.autodesk.com
Subject: Houdini tutorial | Building the orientation matrix for local rotation
I made a little tutorial on how to get local rotation when working in houdini.
Sorry the phone rang at the end of the video.


Ed Schiffer

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Mar 10, 2017, 2:35:45 PM3/10/17
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really good tutorial, Oliver.

thanks

On 10 March 2017 at 08:42, Tim Bolland <Tim_B...@hotmail.co.uk> wrote:

Sent: 09 March 2017 13:39
To: soft...@listproc.autodesk.com
Subject: Houdini tutorial | Building the orientation matrix for local rotation
I made a little tutorial on how to get local rotation when working in houdini.

Build an orientation matrix
Rotate using the orient attribute before the copy sop
Rotate objects after the copy sop.

And it's all VOP !

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Jonathan Moore

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Mar 10, 2017, 3:11:01 PM3/10/17
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Oliver, Hope you don’t think I wasn’t being critical when I mentioned the Point SOP being deprecated in H16. I’d already mentioned that it was a good tutorial. 😊

 

I just think it’s good for those on this list that have just made the move to H16 to do things the new recommend way (avoid using the old Point SOP because it’s single threaded). On that basis you can also add the ‘piv’ attribute through the new Attribute Expression as well. It’s no different than using a Wrangle. It just avoids using two separate nodes.

 

 

 

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Ed Schiffer
Sent: 10 March 2017 19:35
To: Official Softimage Users Mailing List. https://groups.google.com/forum/#!forum/xsi_list <soft...@listproc.autodesk.com>
Subject: Re: Houdini tutorial | Building the orientation matrix for local rotation

 

really good tutorial, Oliver.

 

thanks

On 10 March 2017 at 08:42, Tim Bolland <Tim_B...@hotmail.co.uk> wrote:

Thank you Olivier! 

 

From: softimag...@listproc.autodesk.com <softimag...@listproc.autodesk.com> on behalf of Olivier Jeannel <facial...@gmail.com>
Sent: 09 March 2017 13:39
To: soft...@listproc.autodesk.com
Subject: Houdini tutorial | Building the orientation matrix for local rotation

 

I made a little tutorial on how to get local rotation when working in houdini.

 

Build an orientation matrix

Rotate using the orient attribute before the copy sop

Rotate objects after the copy sop.

 

And it's all VOP !


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image001.png

Olivier Jeannel

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Mar 10, 2017, 5:29:42 PM3/10/17
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No problem Jonathan !
I'm rather happy :)
 Still on 15.5, I'm waiting a bit before switching to 16. I barely use the point SOP, but for the tut I was trying to do it the most classical way, plus I'm a super slow typer, doing it in wrangle would have made my audience fall asleep ;)


2017-03-10 21:10 GMT+01:00 Jonathan Moore <jonatha...@gmail.com>:

Oliver, Hope you don’t think I wasn’t being critical when I mentioned the Point SOP being deprecated in H16. I’d already mentioned that it was a good tutorial. 😊

 

I just think it’s good for those on this list that have just made the move to H16 to do things the new recommend way (avoid using the old Point SOP because it’s single threaded). On that basis you can also add the ‘piv’ attribute through the new Attribute Expression as well. It’s no different than using a Wrangle. It just avoids using two separate nodes.

 

 

 

From: softimage-bounces@listproc.autodesk.com [mailto:softimage-bounces@listproc.autodesk.com] On Behalf Of Ed Schiffer
Sent: 10 March 2017 19:35
To: Official Softimage Users Mailing List. https://groups.google.com/forum/#!forum/xsi_list <soft...@listproc.autodesk.com>
Subject: Re: Houdini tutorial | Building the orientation matrix for local rotation

 

really good tutorial, Oliver.

 

thanks

On 10 March 2017 at 08:42, Tim Bolland <Tim_B...@hotmail.co.uk> wrote:

Thank you Olivier! 

 

From: softimage-bounces@listproc.autodesk.com <softimage-bounces@listproc.autodesk.com> on behalf of Olivier Jeannel <facial...@gmail.com>
Sent: 09 March 2017 13:39
To: soft...@listproc.autodesk.com
Subject: Houdini tutorial | Building the orientation matrix for local rotation

 

I made a little tutorial on how to get local rotation when working in houdini.

 

Build an orientation matrix

Rotate using the orient attribute before the copy sop

Rotate objects after the copy sop.

 

And it's all VOP !


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Fabricio Chamon

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Mar 13, 2017, 5:53:36 AM3/13/17
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thanks for the tutorial Olivier, helps a lot!

2017-03-10 23:29 GMT+01:00 Olivier Jeannel <facial...@gmail.com>:
No problem Jonathan !
I'm rather happy :)
 Still on 15.5, I'm waiting a bit before switching to 16. I barely use the point SOP, but for the tut I was trying to do it the most classical way, plus I'm a super slow typer, doing it in wrangle would have made my audience fall asleep ;)

2017-03-10 21:10 GMT+01:00 Jonathan Moore <jonatha...@gmail.com>:

Oliver, Hope you don’t think I wasn’t being critical when I mentioned the Point SOP being deprecated in H16. I’d already mentioned that it was a good tutorial. 😊

 

I just think it’s good for those on this list that have just made the move to H16 to do things the new recommend way (avoid using the old Point SOP because it’s single threaded). On that basis you can also add the ‘piv’ attribute through the new Attribute Expression as well. It’s no different than using a Wrangle. It just avoids using two separate nodes.

 

 

 

From: softimag...@listproc.autodesk.com [mailto:softimage-bounces@listproc.autodesk.com] On Behalf Of Ed Schiffer
Sent: 10 March 2017 19:35
To: Official Softimage Users Mailing List. https://groups.google.com/forum/#!forum/xsi_list <soft...@listproc.autodesk.com>
Subject: Re: Houdini tutorial | Building the orientation matrix for local rotation

 

really good tutorial, Oliver.

 

thanks

On 10 March 2017 at 08:42, Tim Bolland <Tim_B...@hotmail.co.uk> wrote:

Thank you Olivier! 

 

From: softimag...@listproc.autodesk.com <softimag...@listproc.autodesk.com> on behalf of Olivier Jeannel <facial...@gmail.com>
Sent: 09 March 2017 13:39
To: soft...@listproc.autodesk.com
Subject: Houdini tutorial | Building the orientation matrix for local rotation

 

I made a little tutorial on how to get local rotation when working in houdini.

 

Build an orientation matrix

Rotate using the orient attribute before the copy sop

Rotate objects after the copy sop.

 

And it's all VOP !


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Chris Marshall

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Mar 13, 2017, 2:14:29 PM3/13/17
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And it's all VOP! ? As opposed to what? And what's the advantage / difference?


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Jonathan Moore

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Mar 13, 2017, 2:44:53 PM3/13/17
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The alternative is VEX Wrangles. The advantages is that it’s less effort if you’re au fete with VEX and it will more than likely run faster, which doesn’t make any difference on a small scene but if you’re dealing with hundreds to thousands of transforms it soon counts a lot.

 

The advantages of VOP’s is much like ICE, it’s visual, approachable and artist friendly.

 

VOP’s are threaded too (they generate VEX code behind the scenes automatically) so there’s not much in it for smaller transform challenges. The one gotcha, as you work on larger scenes is that you avoid the old Point SOP as that’s single threaded and even though it’s doing something simple in Oliver’s example, if it’s doing it to 5000 points on a single thread that’s not so good.

 

A lot of artists gravitate towards Wrangles in the long run and save VOP’s for things like procedural noise (which is trickier to manage in Wrangles). VEX snippets in Wrangles is pretty approachable too. The documentation is good and folk like Entagma  and Matt Estella (Tokeru Wiki) includes bite sized chucks of VEX in their tutorials – which eases the path considerably as you’re always learning through context.

 

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Chris Marshall
Sent: 13 March 2017 14:55
To: Official Softimage Users Mailing List. https://groups.google.com/forum/#!forum/xsi_list <soft...@listproc.autodesk.com>
Subject: Re: Houdini tutorial | Building the orientation matrix for local rotation

 

And it's all VOP! ? As opposed to what? And what's the advantage / difference?

 

On 9 March 2017 at 13:39, Olivier Jeannel <facial...@gmail.com> wrote:

I made a little tutorial on how to get local rotation when working in houdini.

 

Build an orientation matrix

Rotate using the orient attribute before the copy sop

Rotate objects after the copy sop.

 

And it's all VOP !


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Olivier Jeannel

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Mar 13, 2017, 2:45:16 PM3/13/17
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Vop is close to ICE.
VOP is the visual version of VEX which is code (coding vector).
In fact, when you build some Vop trees, you can see the resulting Vex code.

It's just me beeing more able to build and read Vop nodes rather Vex lines.


2017-03-13 15:55 GMT+01:00 Chris Marshall <chrisma...@gmail.com>:
And it's all VOP! ? As opposed to what? And what's the advantage / difference?

On 9 March 2017 at 13:39, Olivier Jeannel <facial...@gmail.com> wrote:
I made a little tutorial on how to get local rotation when working in houdini.

Build an orientation matrix
Rotate using the orient attribute before the copy sop
Rotate objects after the copy sop.

And it's all VOP !

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029 20 37 27 57
07730 533 115

Olivier Jeannel

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Mar 13, 2017, 3:16:02 PM3/13/17
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Jonathan, I thought VOP and VEX were running at same speed ? Am I wrong ?

Jonathan Moore

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Mar 13, 2017, 4:28:17 PM3/13/17
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| Jonathan, I thought VOP and VEX were running at same speed ? Am I wrong ?

 

The automatically generated code is messier but should run at approximately the same speed. Any speed advantage will often come by achieving more with less nodes (less chance of other nodes slowing things down unexpectedly).

 

I think the main advantage of Wrangles is that you often find things that can take a good number of VOP nodes are achievable with few lines of VEX. That’s not unique to VOPs, it’s a characteristic of visual programming in general.

 

I’ve got nothing against VOP’s, I think they’re great (I prefer them to ICE in many ways). I was just attempting to answer Chris’s question ref the advantages and disadvantages of each approach.

 

 

 

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Olivier Jeannel
Sent: 13 March 2017 18:47
To: Official Softimage Users Mailing List. https://groups.google.com/forum/#!forum/xsi_list <soft...@listproc.autodesk.com>
Subject: Re: Houdini tutorial | Building the orientation matrix for local rotation

 

Jonathan, I thought VOP and VEX were running at same speed ? Am I wrong ?

Nono

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Jun 30, 2017, 3:41:40 AM6/30/17
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Damn Vex, just found out that you can replace your whole first part by

matrix3 m = maketransform(@N,{0,1,0});
@orient = quaternion(m);

The normal SOP isn't needed too seems houdini calculate it under the hood...

Thanks Olivier


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David Saber

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Jul 9, 2017, 3:30:24 AM7/9/17
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Good job bro!

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