Apply size and rotation to object data...

[madcoo]

Hi guys!

I've been wondering...


Why do we have to "apply size and rotation to object data"?
I do it all the time, but I'm not quite sure about what it does.

I noticed the following, though:
- let's say I create a default cube (size = 2x2x2)
- if I size it down in OBJECT MODE, VISUALLY I'll get a 1x1x1 cube BUT when I go to EDIT MODE it will still be 2x2x2.
- when I apply size & rotation, it changes its size to 1x1x1 in edit mode (i.e the same size as its visual representation)

So I just thought: "The VISUAL size of the object is not its ACTUAL size"

But... here's my question:
What's the point in this?
In what case would it be useful NOT to apply scale and rot?

Many thanks guys!

[Meelis]

Yes thats really weird, i wanna know it too.

[OnoSendai]

Well, it's a Blendigo limitation that should be fixed.

[dakiru]

Hi!
How I understand this: I have a cube, which is 1m x 1m x 1m (or blender unit) and scale this cube to 3m x 3m x 3m. So visually it is still 1:1:1 cube and the scale is 3x. but for Indigo it is important to know whether it is 2 meters or 20 meters. In this case it still will be 1m x 1m x 1m cube for Indigo, because scale is not applied. Practically I can imagine the situation, when I'm modeling the building and when it's finished it is 5 units tall. But then I know that in real that building is 50 units (meters). So, what? I scale it 10x. And it will be: size = 5; scale = 10. After the scale is applied its gonna be size = 50; scale = 1 and this is what Indigo needs.

Guys, please, correct me if I am telling something stupid

edit: I've always thought, that rotation applying is not needed. But I don't know this for sure.

[madcoo]

Hi!

Thanks for your reply, but I still can't see why Blender has this bizarre system of "two scales in one" (a visual one and a real-scale one)...

I haven't used Sketchup a lot, but if I remember well Sketchup doesn't have this "double-scale" thing...

So what's the use for it in Blender

PS: applying rotation gave me some strange results once, but sorry i can't remember why or in which circumstance...

[madcoo]

Hi !

I went "answer-fishing" in the BlenderClan forum...

Here's a MAJOR piece of answer I got:

NOT applying scale and rot is useful in the following example:

- let's say I create an object
- I duplicate it, BUT only as an INSTANCE (Alt+D instead of Shift+D)
- in OBJECT mode, I'll be able to change the size of an instance, but it WON'T change the size of ALL instances - only that of this particular instance
- in EDIT mode, all changes in the original mesh will result in a change in all the instances.
- if you APPLY scale and rot, all your instances will be the same as the original object.

Conclusion:
NOT applying scale and rotation seems to be useful only if you use Blender's rendering engine in order to render instances that are different from the original object.
Whereas Indigo absolutely needs to have the correct scale for every object...


If anyone thinks I'm wrong please post your reply and explain it to us!


PS: QUESTION TO OUR BELOVED DEVELOPERS:
If this explanation is right, would it be possible (in a future version) to have Blendigo apply rot/scale automatically?

Thanks!

[Meelis]

I belive Indigo supports instances but really havent used them never.
So doe's Indigo support blender instances like particles from custom object?

[Jambert]

I belive Indigo supports instances but really havent used them never.
So doe's Indigo support blender instances like particles from custom object?

Good question, I thinck it doesn't but maybe it has changed...