View Full Version : Midevil Trebuchet - LW Dynamics

08-19-2004, 06:52 AM
Here is a seige weapon called a trebuchet I recently completed for the dynamics competition over at CGTalk. It is almost all LW dynamics.

http://beta.usavgroup.com/cgtalk/cgtalktrebfinal.mov (2.3Mb) - Final Entry
http://beta.usavgroup.com/cgtalk/sideview.mov (470KB) - Side View
http://beta.usavgroup.com/cgtalk/final01.mov (1.4Mb) - Following the Projectile
http://beta.usavgroup.com/cgtalk/trebsideview.mov (900k) - Just the Trebuchet

and a still of the weapon below.

P.S. You can go to http://www.cgtalk.com/showthread.php?t=162862 to see some more and vote for your favorite.

08-19-2004, 06:54 AM
and the tower getting hit

08-19-2004, 10:38 AM
Nice :)

08-19-2004, 01:05 PM
I'm gonna vote fer' ya, I hope you win!


08-19-2004, 01:10 PM

I don't know that I will win but I'm giving the Maya guy a run for his money :D

08-19-2004, 01:39 PM
looks cool-
the hit not as much as the sling itselfe- it looked realistic and well made!

08-19-2004, 01:46 PM
All I can say is wow, very nice work - hope you win! You'll be there or thereabouts for sure....


08-19-2004, 02:07 PM
I went to CG and got'em... Yours looks great... I can't view one.. I see yours and one more with a couple of lame looking figures at the beginning operating the thing. It's nice and all but the actual DYNAMICS of his wall collision well... SUCKS!

Yours (and I did not trip on the white) looks like a professional animation from say the Discovery channel. I'm voting for yours because one its LW and two you followed the directions more precisely. If that guy had spent more time on the actuall moves instead of the eye candy (which sticks) (his grass and all is nice though) he'd be closer to your animation...



08-19-2004, 02:39 PM

I did the white because everyone else has dark renders with dark grass. I went a bit more stylized because I didn't have the time to work on landscaping. The dynamics ate most of my time.

08-19-2004, 05:40 PM
let me say that my first thought was that my jaw hit the ground and with that can yuo tell me as simple an to the piont how you did it and the breaking of the wall on the tower and also was this done in lw8 or something else and one more thing can you post some wireframes :D

08-19-2004, 07:33 PM
Yes, please tell me how you did the wall breaking! Amazing!

08-20-2004, 12:48 PM
Well, there isn't any simple way to list it all out so here is a summary:

1 - HardFX on the Arm and CollisionFX on the arm axle. The bottom of the arm is loaded with points to effect the weight. A small gravity effector is placed at the bottom of the arms travel to hold it a second so the weight can catch up. This is all calculated and a makemotion null is added.

2 - The weight axle and weight are parented to the arm null. HardFX on the weight and collisionFX on the weight axle.

3 - Ropes are 2 point poly chains with clothFX. a single point is stitched to the sling where the ball will go. A null is parented to the arm null for the side ropes. 2 bones are hooked to each side rope with the target being the rope null. This keeps one end on the crank and the other on the arm. Higher density meshes are Metalinked to each polychain.

4 - an event is added to cross the sling at the right arch. The single point is set to cut at collision, launching it forward. Some experimenting with settings and cut position was needed to get the best distance. Makepath for that point was used to create the ball null. The ball object was parented.

Oh yea, collision detection doesn't work great so for the ropes I added a special invisible mesh around the arm for a collision object so the ropes and slings don't fly through the wood. The is also a ground collision object to stop any rope from going below ground.

At this point I have the trebuchet firing the ball.

Then for the tower:

1 - I modeled and textured the tower. When it was complete I made a big jagged poly and cut out a hole in the tower and also made a solid piece to fit in the hole. Deleted all the inside polys so all I was left with was the outside wall poly in the shape of the hole. Then I cut it up into small brick shapes with the knife tool. Unweld the points and extrude out the bricks to fit the inner wall. Now this layer is a bunch of bricks ready for explosion.

2 - I added hardFX to the bricks. A parented an odd shaped invisible object to the projectile ball null. It was made byt taking a copy of the ball and then stretching the back end out and wider, kind of like a cone. This object was the collison FX for the bricks. The odd shape made the wall break from the center out instead of all at once.

3 - A particle emitter was added at the point of impact and another collision added to the ball null. The particles were made to look like debris. A whole lot of tweaking was needed to get the right looking explosion.

4 - Again more issues with collisions. The bricks would randomly pop out of the wall so I again made a special invisible mesh that was higher density to keep the bricks from shooting through walls. This stopped most of it but there were still one that pops out of a wall and then magically is sucked back in. They also do some breaking through right at the bottom of the hole. Collision detections need to be updated to poly on poly and not poly on point as they are now.

The explosion is a total hollywood one. In real life the ball could never penetrate the wall on the first hit but that was dull. More of the debris would have gone inside but again. not that visually interesting. If I would have had some more time I would have added a few particle emitters at the windows and top floor to simulate dust coming out.

That's it in a nutshell. I think I remembered most of it.

08-20-2004, 05:46 PM
ouch my brain hurts. :D was that lightwave 8 you were using or something else. P.S this would make a great tut just a thought.

08-20-2004, 05:49 PM
This was Lightwave 8

08-20-2004, 05:57 PM
Ha I just saw your web sight of the photos you have a great eye.
How long have you use lightwave and is photography your job or hobbie.

08-21-2004, 10:24 PM
I like the National Geographic style, but wish you`d swapped the ball for the LW Cow :D


08-21-2004, 10:29 PM
That would be funny but you would have to rig the cow and add sound effects. I don't think I would have finished it in time :)

08-21-2004, 10:31 PM
Originally posted by shaol
How long have you use lightwave and is photography your job or hobbie.

Photography is a hobby. Been using Lightwave casually since 5.6 but more serious for the last year or two.

08-22-2004, 04:46 PM
Great animation, I like the white heavenly background. Looking foreward to a cow version.

08-22-2004, 04:50 PM
Thanks. Don't know about the cow though :)

*NOTE* There is less than 2 days left for voting. You can vote for your favorite one at http://www.cgtalk.com/showthread.php?t=162862

08-24-2004, 05:59 PM
huh, not sure if I made it in time but either way, vote is posted and I loved your job on it.

All the more greater because it was done by LW8(newtek could do a bit of promo on this, truly great stuff)

Either way, good luck and I hope you get the appreciation you deserve(by winning that competition)

08-24-2004, 07:54 PM
I just finally looked at the entries and I think I like yours the best.
To me it seems to be the most realistic - based on the handful of times Ive seen someone launch a car or piano with one of those things!

Plus its obvious you spent more time studying motion & dynamics instead of animating little people ;)

08-25-2004, 02:17 AM
I don't care wath the others made...I'll go voting for you right now :cool: :cool: :cool:

08-25-2004, 09:07 AM
The challenge is over and the results are in. Thanks to everyone that voted (for anyone).


08-25-2004, 09:50 AM
Congrats, truly great job!
Lightwave, still **** competitive, good to know :)

08-26-2004, 12:01 PM
newtek could do a bit of promo on this

LOL, I don't think you'll be seeing any of that from them.

Congrats, truly great job!
Lightwave, still **** competitive, good to know :)

Thanks for the compliments Raptor.

08-26-2004, 01:15 PM
Congrats on the win.