[ODE] XODE - should angles be in degrees or radians?

[Nate W]

On Fri, 19 Mar 2004, William Denniss wrote:

> We could go with the objects=elements and properties=attributes model
> but then we would have to make it consistant thoughtout.  Should the
> other element of joint 'link2' be an attribute as well?  What about
> mass, and torque, and force of Body?  The latter two have multiple
> attributes themselves so it would have to be "torquex" "torquey" etc... 

A "thing" that has attributes of its own should probably be an element.  
For example I'd prefer the torque vector be expressed as <torque x="0"
y="0" z="0"> rather than torquex, torquey, torquez approach.

> Wouldn't having everything as attributes make the file a bit of a mess?

I guess that's an aesthetic thing - I like attributes because they cut
down on mess. :-)

> Personally I think this:
> 
>                     <axis>
>                       <rotation x="0" y="-1" z="0" />
>                       <lowStop>0</lowStop>
>                       <hiStop>0</hiStop>
>                       <vel>0</vel>
>                       <fMax>0</fMax>
>                       <fudgeFactor>1</fudgeFactor>
>                       <bounce>0</bounce>
>                       <CFM>0</CFM>
>                       <StopERP>0.05</StopERP>
>                       <StopCFM>0.0001</StopCFM>
>                       <SuspensionERP>0.05</SuspensionERP>
>                       <SuspensionCFM>0.0001</SuspensionCFM>
>                     </axis>  
> 
> Looks better than this:
> 
> <axis rotationx="1" rotationy="1" rotationz="1" lowStop="0" hiStop="0"
> vel="0" fMax="0" fudgeFactor="0" bounce="0" CFM="0" StopERP="0"
> StopCFM="0" SuspensionERP="0" SuspensionCFM="0" />

And I agree, but only you've indented one and not the other. :-) I think a
fairer comparison would be:

<axis 
	lowStop="0" 
	hiStop="0"
	vel="0" 
	fMax="0" 
	fudgeFactor="0" 
	bounce="0" 
	CFM="0" 
	StopERP="0"
	StopCFM="0" 
	SuspensionERP="0" 
	SuspensionCFM="0">
	<rotation x="1" y="1" z="1"/> 
</axis>

...which I think looks better than either of the above.

I agree about making the rotation vector a child element.  The x/y/z
values form a vector and I think it makes sense to exress vectors as
elements.  One could argue for <stop low="0" high="1"/> but I wouldn't go
that far - there's no common data type with "low" and "high" members as
there is with x, y, and z.

> Do we need to vote on this too?

I dunno... if we get into the details of exactly what should be an
attribute and what shouldn't, it could drag on for a while.  Maybe a vote
on the general approach, though, e.g.

1) keep the current format

2) if an element has no attributes and a single value in its innertext,
make it an attribute of its parent

-- 

Nate Waddoups
Redmond WA USA
http://www.natew.com/