It's possible to apply a displacement of a body along a curve?

Carlos Fondevila

Hi all,

I'm triying to move a bucket along the direction of a belt (represented by a curve) but I can't to apply this movement. It's possible to do that?

Thanks!

GTT Adam

Hi @Carlos Fondevila,

You did not set the independent variable. In this case, it will likely be TIME.

Hope this helps!

Adam Reid

GTT Adam

Hi @Carlos Fondevila,

The Motion is a single constraint that you are placing on the object. So to move it in X and Y you must use two Motions as you describe. The rest of the body must still be constrained, so if your part is rotating then you need to add more constraints like a in-plane joint to keep it aligned along a plane. The Y Motion, instead of with respect to TIME, you can instead set the independent variable as the X displacement of the body via an expression.

The Point-To-Curve constraint is a great option. You will still need one Motion to move the body along the X axis and the PTCV will then take care of the Y axis. So only the X displacement will be with respect to TIME, and the Y displacement will be with respect to X displacement.

You can find a tutorial on the PTCV joint here: https://help.altair.com/hwdesktop/hwx/topics/tutorials/mv/tut_mv_1025_higher_pair_constraints_t.htm?zoom_highlight=ptcv

You can find more on the PTCV joint here: https://help.altair.com/hwdesktop/hwx/topics/motionview/advanced_joints_point_to_curve_define.htm?zoom_highlight=point+to+curve

Hope this helps!

Adam Reid

GTT Adam

Hi @Carlos Fondevila,

Yes! A Motion can set to Using Markers, to assert motion on the marker along various axes using a curve (see below).

https://help.altair.com/hwdesktop/hwx/topics/chapter_heads/motions_r.htm?zoom_highlight=motion

Hope this helps!

Adam Reid

Carlos Fondevila

Hi @GTT Adam ,

For some reason, when I create the Motion with Markers:

I receive the next error:

Thanks!

GTT Adam

Hi @Carlos Fondevila,

You did not set the independent variable. In this case, it will likely be TIME.

Hope this helps!

Adam Reid

Carlos Fondevila

Hi @GTT Adam, I'ts correct, I need to use the TIME independent variable.

Otherwise, I ifnd a little bit difficult the use of the motion with markers to define a profile of movement, at first you need to use two motions for define the X and Y position (you can not use a motion to define X and Y) and also, if you define for example a point of a body and a reference marker to the part it's only picked by a point, and the part rotates without control. Then, I understand that you need to define also the rotate position of the part with another motion.

Do you think that this is correct?

Thanks!

Carlos Fondevila

We have also the Advanced Joint (Point to curve) button, but I triyed it without success, I don't understand the real functionality of this joint, and I don't fin so much information about that.

GTT Adam

Hi @Carlos Fondevila,

The Motion is a single constraint that you are placing on the object. So to move it in X and Y you must use two Motions as you describe. The rest of the body must still be constrained, so if your part is rotating then you need to add more constraints like a in-plane joint to keep it aligned along a plane. The Y Motion, instead of with respect to TIME, you can instead set the independent variable as the X displacement of the body via an expression.

The Point-To-Curve constraint is a great option. You will still need one Motion to move the body along the X axis and the PTCV will then take care of the Y axis. So only the X displacement will be with respect to TIME, and the Y displacement will be with respect to X displacement.

You can find a tutorial on the PTCV joint here: https://help.altair.com/hwdesktop/hwx/topics/tutorials/mv/tut_mv_1025_higher_pair_constraints_t.htm?zoom_highlight=ptcv

You can find more on the PTCV joint here: https://help.altair.com/hwdesktop/hwx/topics/motionview/advanced_joints_point_to_curve_define.htm?zoom_highlight=point+to+curve

Hope this helps!

Adam Reid

Carlos Fondevila

Thank you very much @GTT Adam