[Bf-committers] Bounding box dimensions & linked size patch

[Chris Want]

https://projects.blender.org/tracker/index.php?func=detail&aid=4314&group_id=9&atid=127

Thanks for the comments everybody, and I apologize for the
bad nomenclature in my earlier mail. Above is the URL to a
patch I uploaded to the patch tracker. In the patch I use the
terminology DimX, DimY, and DimZ for the bounding box dimensions
in the Tranform Properties panel, and I've renamed SizeX, SizeY,
SizeZ to ScaleX, ScaleY, and ScaleZ respectively (and for
consistency, I have also renamed other references in the source
that refer to size, e.g. 'Clear Size?' now becomes 'Clear Scale?').

Now to address some comments.

Erwin Coumans wrote:
 > It's not completely clear what the effect of this is. The Collada plugin
 > and Game Engine use the bounding box for the dimensions for rigid bodies
 > (box, cylinder, cone).

This should not have a negative effect on the game stuff and
more than adjusting scale through the transform properties
already does (this really is just another interface to adjusting
scale). If anything it could help game designers calculate
bounding boxes more easily.

Ben Stabler wrote:
 > About the chain icon- you're right, it's very mysterious :P. What about
 > using the proportionality symbol; eg:
 >
 > http://img163.imageshack.us/img163/2053/proportional0bl.png

Ouch, that looks hard to draw in a  15x16 pixel space!

The reason I chose a chain is because that seems to be
a standard icon in 2D programs when you want to retain
aspect ratio. I would appreciate it if somebody with
some icon design skills could create a chain icon
(and a greyed out broken chain for when the button is
off).

Chris Burt wrote:
> When I originally attempted this I labeled my buttons "DimX, DimY, and 
> DimZ" referring to dimensions.
> 
> Mr. Want: You have my vote on committing this with the changes above. I 
> think its a great idea for a feature (I've had a use for it many times) 
> and I think it fits perfectly there in the UI.

Thanks Chris, and I apologise for the bad nomenclature. Using
DimX/ScaleX, etc., seems to be a nice way to go. The only
small issue with renaming Size to Scale is that the internal
data structures all use the name 'size' for this quantity.
But, that's under the hood and not visible to users.

Matt Ebb wrote:
 > I read your message and saw the screenshot, but I still don't really
 > understand what's going on there. I think it needs to be made clearer.
 >
 > What does adjusting the 'bounding box' actually do? Does it mean that
 > potentially even if an object's vertices are only 1BU wide, the  object
 > itself seems 2 BU wide even though there's nothing there in  that extra
 > space? This seems pretty weird, even by Blender standards.  What would
 > it be useful for?
 >
 > As a side note if anything is going to happen there, it would really  be
 > a good (and long-overdue) thing to change the word 'Size' to  'Scale'.
 > The word size is very misleading, since it doesn't define an  absolute
 > size, but the scale from a somewhat arbitrary reference  point, and many
 > people have been confused by it.

Sorry for the confusion, Matt. I've implemented what you've mentioned above,
and I hope this makes things clearer.

Basically, I have two motivations for implementing this:

1) When I was teaching a course last week, I had a lot of students spend
*way* too much time trying to create a cube that was 50m x 13m x 0.5m:

http://bebop.cns.ualberta.ca/~cwant/inkpoint/slides/slide0088.html

Now, granted, I may not have gone about it the best way, but now
I can tell them to 'Create a cube and set the dimensions to 50x13x0.5),
and what used to take 10 minutes for a n00b, now takes 10 seconds.

2) For 3D printing I often get files that need to be scaled to fit
in the machine. This patch, along with the ability to change size
uniformly, makes it effortless to make the piece fit within a
build size to an exact dimension.

Thanks everyone!

Chris