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View Full Version : A Little help with Spline Control



Sean Martin
07-09-2014, 08:45 AM
Hi All,

I've been trying to animate a ribbon swirling around an object using Spline Control, unfortunately I keep hitting a wall. The problem is when I adjust my spline path I keep getting some very ugly twists and kinks in the spline ribbon, which is effecting the object attached to it in the same way (see the image attached). Is there a way to get rid of those twists in the spline ribbon? I've reviewed the Tuts and content and I still can't figure out what I'm doing wrong! Any help or suggestions much appreciated.

Slartibartfast
07-09-2014, 09:20 AM
You can sort it out by rotating the heading of the nodes so the little heading-arrow (red one) is pointing along the spline (tangentially)

RebelHill
07-09-2014, 09:32 AM
Yup... as pointed out, you want to orient the spline control nulls/nodes to "point" along the direction of the spline itself.

See here for more detail on all the lil tricks n details of spline control...

https://www.youtube.com/watch?v=gCVneRb141I&index=17&list=PLTds3QePYrWEWipwKkLmyNT4Tf_JTigM2

Ma3rk
07-09-2014, 09:37 AM
Quick answer is that you'll need to select the bones and rotate them on the Bank.

Longer answer is that I'm guessing you created the spline originally in Modeler and then used the conversion script in Layout. I submitted a bug report about this a couple months ago but haven't heard of a resolve yet.

What you can do though if adjusting the Bank doesn't do the job or becomes an exercise in futility is to create the spline from scratch within Layout. It's pretty straight forward using Nulls and the correct parenting structure. On of Rebel Hills tuts on YouTube explains it quite clearly. Using the problem spline, simply drag position the new nulls in the proper order to re-create the desired shape. The resulting curve and banking at each node should now behave as expected.

M.

Sean Martin
07-09-2014, 09:42 AM
Thanks for the quick reply Slaribartfast, your suggestion worked. After much rotating on the heading I seem to have got rid of most of the kinks. Still needs a bit more tweaking but I think I'm heading in the right direction now. No pun intended!

Rebhill, I did watch your vid and some of the Newtek ones as well. Ma3rk I built my spline ribbon in layout from nulls, the funny thing is I had this working a while ago on another project.
Nothing like a looming deadline to screw up your head. Getting some nice results now, I'll sleep a little better tonight!. thanks for all your input.

raw-m
07-09-2014, 02:58 PM
I submitted a bug report about this a couple months ago but haven't heard of a resolve yet.



Got the bug report link, Ma3rk? I've been using this script without issues, other than tweaking rotations. Would hate to run into it, was wondering how you arrived at your problem.

Ma3rk
07-09-2014, 04:15 PM
Got the bug report link, Ma3rk? I've been using this script without issues, other than tweaking rotations. Would hate to run into it, was wondering how you arrived at your problem.

Managed to find it:

https://fogbugz.newtek.com/default.asp?70902_bso5nhpc7ph1qikh

I was following Jennifer H's. tutorial and adapting that for some "tank treads" for a robot model. A pretty simple spline in a trapezoidal shape with less than 20 nodes. I might have been able to correct it rotating bank values, but when I rebuilt it from scratch it all worked perfectly from the get go.

Had another issue with instanced geometry on the Spline and Motion Blur that I never did figure out what was causing the problem. Seemed to be something outside of the spline and instancing making it really tricky to isolate. I'll revisit that again at some point but ambition has waned for the present. Did a quick fix using an envelope on the MB value when the treads came to a stop.

M.

raw-m
07-10-2014, 07:32 AM
That reminds me of a tip Jen once gave in a LWUG discussion. I've looked but I can't find the link.

Off the top of my head, the tip is something like this....

Setup your Spline Control, so you have all the nodes etc.
Select all the nodes that make up Spline Control.
With them all selected, open Motion Options.
Under Spline Control, select the master Spline Control null (as you would if using other objects).
The nulls should then jump to the orientation of the path.
Create a keyframe for them all and then set Spline Control back to none for all of them.

I think that was the setup anyway, not at computer right now.

Ma3rk
07-10-2014, 10:09 AM
That reminds me of a tip Jen once gave in a LWUG discussion. I've looked but I can't find the link.

Off the top of my head, the tip is something like this....


I vaguely recall something like that several months ago. Was going to show her this problem at the last meeting, but it got cancelled. Still will when a date gets set for the next one.

M.