View Full Version : Suspension Animation Issues

October 11th, 2011, 11:44
Hi folks, I am having some issues with a current project and could do with some assistance.

The problem lies with the animation of the landing gear 'scissors' in FSX (+Accel) as can be seen in these shots...


For some reason the scissors are 'passing through' each other rather than moving the way they were set up in GMAX.

I have redone the animation in GMAX at least three times and it is correct there (i.e. both parts of the scissors remain connected at the mid point joint with key frames every 10 frames) and I have spent several hours messing with contact point data especially in the areas of compression ratio and damping ratio with no luck. The main gear scissors are the worst case although the nose gear scissors also show this effect to a smaller degree but do not pass through each other and so the effect is less noticeable.

I am starting to think I may need to add some sort of constraint to the animation in GMAX to 'force' the lower scissors to stay connected to the upper scissors/joint pin but I have no clue how to do this nor which type of constraint to apply.

Has anyone seen behaviour like this before and can anyone offer suggestions on how I might fix it.

Thanks for looking.

Dev One
October 11th, 2011, 12:06
Tako, Make sure to start with that your animation slider starts at frame 100 - I have to shift it along to that after setting the deflections at 150 & 200.
This can make it look as if its wrong.
For my Provost the top link has its designated animation pivot between the fixed leg & the top pivot of the link. For the bottom link the designated animation pivot is the bottom pivot connected to L_Gear ( or R_Gear). Looking at me Gmax I'm not in perfect co-incidence with the link to link pivot & I find its a bit of a hit & miss affair to get them together, but a marker point on ones screen is the 'bodge' I used!
After thought - that works for me on a fixed u/cart, so a retractable might be a bit different......

October 11th, 2011, 12:18
Thanks for responding so quickly Keith. My animation slider starts at frame 0 but the scissor animation takes place from frame 100 to frame 200 (the first 100 frames are used for the gear lowering animation).

On my upper scissor the pivot point is at the swivel point on the upper part of the leg and it is attached to the upper leg. On my lower scissor the pivot point is at the swivel point on the lower part of the leg and is attached to the lower leg. This sounds identical to your set-up to me.

To align the parts during animation I have been using 'circles' pivoting on the scissor pivot points and the scissors also have holes through them for the hinge pin which makes lining them up fairly easy but they don't stay 'locked' together in FSX for some reason.

October 12th, 2011, 11:06
Thanks to Mathias and Tom over at the FS Developer forums I now have a correctly working animation. :)

Apparently all my animations were 'non-linear' (I can't remember the exact term now) so I remade all the scissor animations setting the animation rollout tag to linear as suggested and it now works fine in FSX with no crossing of the scissor parts during the animation.


These are for Tom and Mathias.... :icon29::guinness: :icon_lol:

October 12th, 2011, 11:44
And me a teetotaller.....! :icon_lol:

October 12th, 2011, 11:48
LOL..in that case imagine the dark one is Coke or Pepsi! :icon_lol:

Dev One
October 13th, 2011, 00:09
Ahhh....Basic settings, I must admit that I have linear set as the default & hence forget that its there!