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Thread: Want to activate Bullet Dynamics 515 frames into my animation

  1. #1
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    Want to activate Bullet Dynamics 515 frames into my animation

    Within my scene (File 01) I have 14 characters appearing from the right to make 2 words floating 4m above the ground plane, at frame 435 they are all at rest. From frame 525 I would like them affected by Bullet Dynamics. In another scene file (File 02) the Bullet Dynamics takes 70 frames for the characters to come to rest on the ground plane (I’m happy with all the settings). How do I activate the Bullet Dynamics starting at frame 515 in File 01 to finish at frame 585?

    From frame 585 I would then like the characters to remain stationary for a further 3 seconds before they will all fall through the ground plane to disappear from sight. I’m assuming the Bullet Dynamics will have to be deactivated some how from frame 585 for the remainder of the animation, how is this accomplished please? I have searched for the solution within the documentation and YouTube etc etc without success.

    Help would greatly be appreciated to achieve the above.

    Many thanks

    Munty

  2. #2
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    In the World Properties tab, there's a Start Offset to specify the first frame for dynamics to be applied. As well, you have an optional Envelope on the Time Scale, where you could ramp it down to 0.0% during the period you want the characters at rest, then ramp it back up when you want them to fall through the floor.

    These, of course, won't work if there are other Bullet items in the scene that you want to be active either before your "start frame" or during the Time Scale = 0.0 period.

    mTp

  3. #3
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    Initial activation/Activate on last key perhaps? and set a key at where you want it to fall.

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    Hi mTp

    I forgot to mention that I am using Lightwave version 11.6.2 if that makes any difference? Unfortunately I can’t see the Start Offset within the World Propertires tab? All I can see are 3 fields to alter the Dynamics Gravity (x,y,z) and another field Dynamics Framerate (fps) which has 2 fields to alter, one being the option to alter the Dynamics Timescale. Firstly I altered the Dynamics Gravity on the y axis only by using the Envelope Button (0 gravity from frames 0-525, then -9.8m from frames 526-596, then put the gravity back to 0 from fame 597 onwards) with no luck, the Dynamics didn’t kick in at all when anticipated? Secondly I altered the Dynamic Timescale field using the Envelope Button (0% from frames 0-525, then 100% from frames 526-596, then 0% from frame 597 onwards) again with no luck, the Dynamics didn’t kick in at all when anticipated?

    For each of the Gravity and Timescale settings I used the 4 variants under the Activation tab - Initial Activation, Start Active, Start Sleeping, Active Always and Active On Last Key. None of these variants have worked?

    There are no other Bullet items within y scene apart from the letters I have previously mentioned.

    Have you any further suggestions or have I misinterpreted your initial explanation?

    It would have been far simpler if the software programmers had a button to activate Start Dynamics at frame ? and End Dynamics at frame ?.

    I would welcome your continued help.

    Kind regards

    Munty

  5. #5
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    For me, it does appear the Gravity.Y envelope is broken in LW 11.6, but the Time Scale envelope works as expected. I'm running Ver 11.6 Build 2723 (Win64) 30-Oct-2013. You may have left Gravity=0.0 in Y from your Gravity envelope test for your Time Scale test. Sample LW 11.6 scene attached.

    Click image for larger version. 

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    mTp
    Attached Files Attached Files

  6. #6
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    Hi mTp

    Thank you very much for posting a zip file for me to look at, I am very grateful. After reviewing the Scene file, it appears I have used the same method in one of my earlier attempts but with not the same affect you have achieved? In my effort with seemingly the same inputs you have used I can't seem to get my characters to move in from the right, they just stay stationary for the whole time the Dynamics function is being calculated? I hope you don't mind but I have included a Scene file + Objects for the characters movie. In this scene I am trying to have all 14 characters fly in from the right to make up a word, then the characters fall to the ground plane, once they are stationary the will then disappear through the ground plane they are resting on. Also I have included another Scene file just showing the Dynamics occurring just how I want, hopefully you will be able to get the same Dynamics occurring within my Characters scene between Frames 451 and 521?

    Thank you very much for your help.

    Kind regards

    Munty
    Attached Files Attached Files

  7. #7
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    Well, it doesn't work as expected in either LW11.6 or LW2015 using the Enveloped Time Scale, IMO. It works in LW2015 using the Start Offset, and in LW2018 is much faster simulating.

    RE: your scene file, you would want to set all of the letters to have "Activate on Last Key" in the Activation tab of the Bullet=>Item Properties panel. You can select all the letters by selecting the first, and use SHIFT-LMB to select the last, go to the Activation tab and select Activate on Last Key. This causes Bullet not to be applied until after their last keyframe.

    In LW11.6, there appears to be a Bullet bug which prohibits the X translation prior to activation. Once the Rigid Bullet property is applied, it allows the morph deformations but not translation.

    In LW2015, the X translation to move them to the middle of the screen works, BUT is then *repeated* when Bullet Time Scale goes to 100%, the letters RE-appearing from the right and when they stop (last keyframe), they start dropping to the floor individually. It does work correctly in LW2015 and LW2018 using the Start Offset parameter.

    As well, I don't know of any way to have Bullet make the groundplane become porus to the letters. A simple solution might be to have a non-Bullet copy of the floor overlay the Bullet version and then just lowering the Bullet floor to have the letters sink through the non-Bullet floor would probably work OK.

    In the case of LW11.6 (assuming you're not planning to upgrade), I'd probably recommend rendering three separate scenes and appending them for the final sequence: 1) letters fly in with no Bullet at all in the scene, 2) the already placed letters have Bullet applied and hit the floor (as in your your 02 sample scene), and 3) use Save Transformed Objects to save the letters on the floor in there final positions, bring them into a third scene, set the ground plane as either not a Bullet object at all or have a large mesh / collision margin to have Bullet sink them through floor, or use the sinking Bullet floor trick described above.

    Unfortunately, it looks like Save Transformed is only available on each individual letter, so that'll be a little cumbersome (i.e. save each letter separately rather than in layers of a single object).

    mTp
    Last edited by MonroePoteet; 03-18-2018 at 04:28 PM.

  8. #8
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    Hi mTp

    Thank you very much for all your efforts and invaluable advice. I’m glad I’m not going crazy and that it’s the software inadequacy not me, I can now stop banging my head against a brick wall.

    I too was thinking about creating three scene files as a last resort solution to perform the three phases of the animation, I’m glad you suggested that method also.

    Kind regards

    Munty

  9. #9
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    Glad to help! Other than having to save each transformed letter separately, it should work pretty well. You can then either use LW to append the three resulting image sequences (Backdrop objects with the image sequences mapped using stepped Dissolve envelopes and the Start Frame field in the LW Image Editor panel) or a video editor.

    mTp

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