BongoRotatePivot, BongoPivotLock, BongoCopyChain, document keyframes


#1

What is the purpose of BongoRotatePivot command?
(There is similar undocumented command named BongoOrientPivot.)

What is the purpose of (undocumented) BongoPivotLock command?

What is the purpose of (undocumented) BongoCopyChain command?

Can Bongo rotate object about arbitrary line?

Green keyframe markers represent document keyframes. Margaret told me that sun position is example of document keyframe. She promised to explain document keyframes in the help file, but she did not. Do you know more examples of document keyframes?


#2

EDIT: Updated picture, plus more answers.


Rotate Pivot: Sometimes you want to have the Pivot aligned to/with your objects instead of Worl, which is default when you drop an object on the canvas. Here I draw a Line (selected, and the Pivot is aligned to World), and a Point on left side on the line, also World.

Now to rotate the pivot for the Line (attention, not the point in the square)): The RotatePivot command is found only on the Properties-Panel Menu (not on Bongo’s main menu, as irritating as it is…),

… and no to rotate the Point’s Pivot, and then it looks like so (first reference point = along World X).

Make sure you do not use Perspective view when rotating the pivot, the Rotate Pivot command will most certainly fail if you do. Use Top/Front/Left/Right views, only) :

… then click in the align direction :

… and so the Point’s Pivot it is aligned after clicking in the desired direction :

(Sorry, had the wrong picture, now updated)

This kind of alignment is required if you for use Telescope in a non-World direction, for example.


[quote=“Andrew_Nowicki, post:1, topic:44069”]
What is the purpose of (undocumented) BongoPivotLock command?[/quote]

I’ve never used that one, don’t know.

[quote=“Andrew_Nowicki, post:1, topic:44069”][
What is the purpose of (undocumented) BongoCopyChain command?[/quote]

Just a kind of “wizard”, it does only what you would do your self manually, if you do it in the “right order”. I never use it, because I think in arbitrary order and so… a link here and a link there is just as good. :slight_smile: At least it ends up being the same thing at the end of the day.

[quote=“Andrew_Nowicki, post:1, topic:44069”][
Can Bongo rotate object about arbitrary line?[/quote]

This is where the Pivot comes in. You can rotate any object at any position. But this means that you need to move an object’s Pivot to the position where you want to have the “hinge” (and sometimes you would also like to align it,. but as said, only if you plan to slide along something).

Typically a line-end is a desired pivot/hinge point, but you can place the pivot anywhere on a Line/object. The just type in your rotation values in the keyframes.

[quote=“Andrew_Nowicki, post:1, topic:44069”]
Green keyframe markers represent document keyframes. Margaret told me that sun position is example of document keyframe. She promised to explain document keyframes in the help file, but she did not. Do you know more examples of document keyframes?[/quote]

I’ve never used that one, but I recall how puzzled I was before I could see object properties in the Keyframe editor (the sun is an object just like any other object in that regard). So I came up with the idea to start with selecting ALL the objects I plan to include in the animation, then click Move Pivot - but I’m not actually moving anything, I just click the “Reset” option on the command line that shows up, and confirm with RETURN.

This will make all the objects show up in the Bongo Tree View. I use to use that one for naming objects and keeping a structure even when NOT using Bongo for animations… :slight_smile:

Hope this helps you to proceed.

// Rolf


#3

One more thing about RotatePivot. Instead of rotating the pivot like I did above (which is sometimes a bit tricky, I first placed the objects in the desired direction, and then I rotated the Pivot), you can place the objects on the canvas aligned to World, then Reset the pivot rotation as described above), and only then you rotate the objects. This workflow is often (but not always) easier then the other way around-

// Rolf


(Luc Adriaenssen) #4

BongoRotatePivot rotates the pivot, relative to its object. This can useful to let the object rotate about an arbitrary orientation other than a World axis.

The object’s Bongo Property “Rotate in worlds pace” has to be unchecked in order to make the object rotate along his pivot’s axis rather than the World axes.

As Rolf pointed out rotating a pivot can also be useful for IK-joint to act along a specific direction.

BongoOrientPivot is the result of a discussion on this forum Having trouble matching up objects. Is this a job for IK.
It is a variation on BongoRotatePivot which facilitates the orientation of a pivot’s axis to a specific non orthogonal direction in space, whereas BongoRotatePivot operates in a plane parallel to the viewport’s CP (construction plane).

BongoPivotLock is the command version of the checkbox in the Bongo’s Properties panel “Lock to pivot”. By default the pivot is “locked” to the object hence the pivot moves and rotates along with the object. Unlocking the pivot allows translocation and rotation the object while the pivot remains unchanged. This can be useful to modify objects in a Hierarchical chain (so also a IK-chain) without changing their mutual relations based upon the pivots.

BongoCopyChain is the result of another discussion Having trouble matching up objects. Is this a job for IK.
When a Hierachical chain is copied using Rhino’s Copy command the copy children will be relinked to their initial parent and not to the copy-parent, hence corrupting the (IK) chain logic. With BongoCopyChain the links are copied along, so to speak. The command starts by selecting the pater familias and then automatically selects all of its children, grandchildren etc…

Apart from the sun properties a document keyframe can manage the frame number of a RPC (animated figure) object. See http://bongo.rhino3d.com/page/rpc-animation


#5

Wops! I misread. I read “Bongo LinkChain” instead “of Bongo CopyChain”. Sorry.

Good command btw, I didn’t know about that one. Should be added to the help files (a lot is missing there… :slight_smile: ).

// Rolf


#6

Thank you Luc.:smiley: I am surprised by the quality and speed of your response. I believe that McNeel should pay you top-level salary for improving Bongo help file.

What is the purpose of (undocumented) hoseBongoIkCache command?

[quote=“RIL, post:2, topic:44069”]
when you drop an object on the canvas
[/quote] You probably mean the construction plane.

Off-topic comment:
I wonder whether McNeel has clear vision of how Rhino should evolve. At present the main emphasis is on subdivision surfaces. What will they do next? Rhino is not the best program for making models of dinosaurs, but it is evolving in this direction. If you can make models of dinosaurs, you also want to animate them. Bongo cannot do it, so Rhino users will need another plugin for this purpose. Another path of Rhino evolution is non-linear finite element method. Abaqus and ANSYS make tons of money in this field.

Off-topic factoid:
total number of commands: Rhino = 857, Bongo = 73, Flamingo = 26


(Luc Adriaenssen) #8

As far as I know the hoseBongoIkCache command is for debugging purposes and unnecessary for users.

I created an issue on the bug-list concerning the missing command describtions.