edit *.wrl file, add a new node

I tried to add a new transform node in my virtual world object. With Matlab function vrnode I have been able to obtain the handle and set some of existing field of the virtual world object. I am wondering HOW can I add a new transform node under the existing transform node via Matlab directly without manipulating the raw *.wrl file.

Below is the list of fields available. It seems to be that the addChildren field here shall add a new child node to the existing node, so I tried syntax to use the addChildren field, but none of them works. Is it possible? Below is the list return by fields function.

Thank you.

    Field                Access          Type            Sync      
    -----------------------------------------------------------
    addChildren          eventIn         MFNode          off       
    removeChildren       eventIn         MFNode          off       
    children             exposedField    MFNode          off       
    center               exposedField    SFVec3f         off       
    rotation             exposedField    SFRotation      off       
    scale                exposedField    SFVec3f         off       
    scaleOrientation     exposedField    SFRotation      off       
    translation          exposedField    SFVec3f         off       
    bboxCenter           field           SFVec3f         off       
    bboxSize             field           SFVec3f         off

Answer 1

[Jan Houska]

Hi Steven,

as the parent field, you should use the children field, not addChildren, which is an event. Like in the following code snippet, based on the shipping vrbounce example:

w = vrworld('vrbounce');
open(w);
parenttransform = w.Ball;
newtransform = vrnode(parenttransform, 'children', 'NewTransform', 'Transform')

[Steven]

Thanks. I finally created one. BUT the new transform does not apply on the object when I pass new rotation parameter to it. The original object transform node does control the rotation and translation perfectly, but the new sub-node doesn't seem to control anything. Did I put it under the wrong parent node? The reason I implemented these code is because I want to make a multi-rotation of a object toward two axes.

Thanks

[Jan Houska]

Transforms apply only to their children. They do not apply to their siblings. So if you have created the new transform as a sibling of some existing nodes, it would not apply to them.

BTW, have you tried the interactive 3D World Editor? It shows you the effects of your changes immediately and gives better understanding of what's going on when you add a node. You can then always return back to command line if you prefer.

[Steven]

Thank you so much. I finally figure out how it works.