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BLSmith

Using Rotation to Drive Position

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  • My animation is aimed at slowing down an engine and showing various angles. I'd like to eliminate bouncing and that gap entirely. I don't know enough about expresso to come up with a formula, much less the operators that exist that I should use. 

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    I applied my setup to the scene file you provided for "TAPPET1".

    Tappet bounces quite a lot.

    I suspect very poor and faceted nozzle mesh (CBR would tell). I can't fix this in xpresso. Think about remodeling it and giving it a proper subdivision and edge smoothness.

     

    And the function for the Y position, if you want to keep the Tappet at current rotation (-25.698 °) is: Y=0,481*X-58,7

    X and Y position of the tappet is driven by xpresso, Z value can be changed by hand.

    GEAR_QUESTION_C4D_CAFE_JM.c4d

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    23 minutes ago, MJohnny said:

    I suspect very poor and faceted nozzle mesh (CBR would tell).

    Yes I too did tests in the actual scene and had the identical problem :) Although geo is properly terrible, I was still surprised to find that this was affecting the bounding box so massively - MJ's was so smooth and lovely. But what I don't fully get, and part of the reason I didn't investigate / advise further is that I thought the bounding box was square, no matter what the object inside it was doing - it is the bounds after all, surely ? And if it is square then I don't understand why there is no bumping on the corners (if you see what I mean) in MJ's file...

     

    But if you (MJ) think that remodelling the nozzle bit will fix this, and allow this method to work, then it is at least a relatively easy thing to try, @BLSmith ! I can certainly help you with that if you need it...

     

    CBR

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    Remodeling might be the best chance here. I can only compare to the scene which I made couple posts above. Setup is the same.

    Can't find another reason why in OP's scene the tappet bounces more than in the file I provided.

    • Namaste 1

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  • Thanks for applying the principles you've been conveying into my model, and I totally see where you are coming from.

     

    This has taught me a lesson in regards to model quality, and I've since begun a process to try and find the original CAD model, acquire a license for it, and then potentially find a better way at importing the model to C4D so that I can retain as much of the original model as possible rather than get a loss of quality as I have here. I know nothing about importing/exporting, so I'm sure that'll be a fun road to travel on once I get the CAD software. 

     

    I think I'll stick to key frames for now while I work on other components of my model to animate, but I will apply these lessons once I have a model worth of using a bounding box. One day I'd love my entire engine animation to be driven by xpresso so I can adjust the entire animation on the fly, but I suspect that'll be at least several years down the road. 

     

    Cerebera, as far as modeling a new nozzle/lobe is concerned: I'm such a noob at it, and while its totally possible, I'm going to do my best to find a proper file first to import before going down that road. I can hardly draw stick figures IRL much less model in 3D, I'm scared of it lol!

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  • I managed to acquire a higher point count lobe/nozzle and managed to do what you guys recommended, worked great! Thanks so much! Here is a video recapping the thread. <3

     

     

    /thread

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