Normal orientation using vop

[sadhu]

Hello friends.

I am learning vop - matrices and so want to find a solution using vops.

I have animated geo with normals [-1,0,0.2]. I want these normals to orient as per the animation but as they are fixed normals, they keep pointing to [-1,0,0.2]

I tried few things , they work but only when animation is just rotation in y. As soon as I add rotation in any other axis it doesn't work. Please take a look at the attached file and help me to fix this problem.

Thanks for your time.

EDIT -I don't have access to animation but just have dumped out geometry without any useful info like N etc. I can not access tx ty tz or rx ry rz parameters.

Normal_orientation.hipnc

Edited March 18, 2013 by sadhu

[acey195]

you will need to do the normals before the animation, so the transform should be placed at the bottom, below the vopsop

Edited March 17, 2013 by acey195

[sadhu]

I want to find the solution using vop and matrices as I want to learn it. I have done what you have suggested in the ' desired result ' network in my file.

Edited March 17, 2013 by sadhu

[acey195]

ahh ok, I'm sorry in that case. Matrices are kind of complicated, it seems however you are on the right track.

possibly you need to invert some of your connections or values (align B to A instead of A to B ).

Edited March 17, 2013 by acey195

[sadhu]

Hey acey195 don't be sorry. Actually I have just reproduced the problem that I am facing. I don't have access to animation but just have dumped out geometry without any useful info like N etc. So I added Normals facing the previous point number this way I can keep them facing in certain direction through out the animation. Then I am finding the difference in desired direction normals and the normals which are facing previous point and then rotate them as per the animation. But its not working.

Can someone please point me in the right direction to solve this using vops.

Edited March 18, 2013 by sadhu

[tjeeds]

This is really easy to do without vops using the AttributeReorient node, but if you want to do it in vops (or if you just have points with orientations and no mesh) you need to create a static and deforming coordinate system for each point. Both examples are contained. A note on the vops side, having an incorrect N on your geometry screws up the Polyframe node, which is why it's necessary to rename it something else.

Normal_orientation.hipnc

[sadhu]

Hi Jess. Thanks a lot for your help.

Good to know that there is a node which does this. This node must be doing something similar to what you did in 'Hard Way' .

A note on the vops side, having an incorrect N on your geometry screws up the Polyframe node, which is why it's necessary to rename it something else

Now I know why polyframe node was giving me trouble to point N to first edge and I ended up using oldschool way of N orientation. I am wondering how did you find out this problem?

I am studying your file.

[tjeeds]

No problem These are fun things to work on.

As for the N vs. Polyframe issue; I just visualized the normal, tangentu and tangentv vectors that the Polyframe creates and saw that the normal attribute was being overridden by N. Assuming your topology isn't being deformed, the vectors should stick to the local space of each point.