If I put out a Curve SOP and NURBS / Breakpoints so I get a nice tension between the points in the Curve, then I want the start and end points normal.. so the Sort SOP with a Point SOP and delete the first point with odd normal trick doesnt work…then what ? can it be solved ?

And I realy would like to get the normal so it corrosponds with the tenision of the NURB between the points…hrm..

depending on ‘how precise’ you need this to be, you might consider resampling the NURBs curve before computing the normal (by normal, I assume you mean the direction vector to the ‘next point’).

once resampled it's a simple matter of computing P2-P1 to find the direction vector. the Polyframe sop is AWESOME at doing this kind of thing – visualize the tangentu attribute that it outputs.

You can then attrib-transfer the vector to your base curve.

Holler if you need more help!

Best,

G

ps: beware of animating your base NURBs curve as it will lead to the results of the resample sop different for every frame. If that's the case, you'll need to get clever-er… :wink:

Ah Keyframe, always good help from you, the Polyframe SOP did exactley what I wanted!


Thanks alot !

/M

Continued questions about curvers..

I know you can with the path object set 0-1 value it will move back and forward of the lenght of the curve, but can I acess that same information down in SOP's level somehow ?

The answer is (as usual) yes and no.

No, in the sense that there is nothing built in to help you in this regard.

Yes, in the sense that you can easily create it. You can use the carve sop (in extract mode) to pull a single point then use the copy sop to copy a piece of geometry to it.

As a matter of standard practice I typically create a ‘u’ attribute (fit($PT, 0, $NPT-1, 0, 1)) – this will allow you to index a curve using attributes much like you would do top-side!

G

Im not sure what you needed the Carve SOP for but the adjusting the fit command to cos( (fit($PT, 0, ($NPT-1), -90, 90)) ) did the trick.

I wanted to have a value along the curve which was identical at start and end and different in the middle so I essentially could use it to change radius or other things copy stamped to points in the curve

Thanks again Keyframe !

ha ha. yeah… I totally misunderstood your intentions.

When you said path object, I naturally assumed that you want to animate something moving along the path.

I failed reading comprehension when I was little

G

Then again maybe I could have explained better

And I failed double spelling things…so for me “speling” and “spelling” is pure dum luck if I get right

It all just comes to show my theory, smart people fail in simple tasks…hmm haha