10
$\begingroup$

Many times I've banged my poor overworked, under performing head at both virtual and physical walls trying to understand why do we have the object scale attributes when every time we want to apply a modifier or perform some operation the object scale has to be exactly one in all three directions if we don't want our result to look like creations from other dimensions: a sane object scale

How is this feature useful and why is it still in Blender?

$\endgroup$
  • $\begingroup$ So many great answers, so little green ticks... $\endgroup$ – groundjet Oct 8 '16 at 18:40
10
$\begingroup$

Here is how it really is under Blender's hood:

  • An object is just a holder for a mesh, curve, lamp, camera, etc..
  • Multiple objects can share the same mesh (same data).
  • Object adds (among many) transform properties to the data contained within - like location, rotation and scale.

So if you scale a cube into a block, the mesh is still a cube but the object is a block. You can have the same cube mesh linked in many objects, each being a different block.

When you apply the scale (or any other transform) you make the mesh actually reflect the transformation. This change would project into all other objects with this linked mesh.

Some Blender operations only operate on mesh and don't take object transformations into consideration - like UV unwrap for example. That's why scale needs to be applied.

The confusion is imho Blender's fault. In edit mode it should actually display what the mesh really looks like (like it does with modifiers), or these operations should be written properly to account for object transforms - so what you see is what you get - a thing every gui and program should follow..

$\endgroup$
2
$\begingroup$

Additionally to the above answer Scaling doesn't necessarily need to be always applied, most modifiers work well with it, although common problems stem from non applied or non uniform scale.

It is however a valid transformation method, even if temporary, and is also often useful for animations, like stretching effects, growing poping up, etc..

Correctly used it can save a lot of resources by using scaled instances of the same cloned objects, instead of having different meshes just for different sizes

$\endgroup$
1
$\begingroup$

I'm not sure if this will answer your question, but I'll give it a try.

You can scale your objects using either the "Scale" fields, or the "Dimensions" fields: Suzanne1

While you can give your object exact dimensions using the "Dimensions" fields, you can alternatively use the "Scale" fields to, say, reduce or increase your object's size by a given %.

Let's say I want to stretch Suzanne's head (whose dimensions on x,y,z are: 2.734, 1.703 and 1.969 respectively) a 25% on the z-axis. What I'll do is grab the z field inside of "Scale" and change it from 1.00 to 1.25:

Suzanne2

X and Y dimensions remained the same, but the Z dimension increased by a 25% with respect its old value. Now I simply go to Object > Apply > Scale to tell Blender: "Hey buddy, these dimensions will be considered from now on as the default dimensions upon which I'll be working on. Take them as the REFERENCE for subsequent operations":

Suzanne3

How would I increase the Z-dimension by a 25% without the "Scale" field? I would need to type inside of the Z-field inside of "Dimensions" the following: 1.969+0.25*1.969

So, the "Scale" fields are there for pure mathematical convenience, as far as I know.

$\endgroup$
  • 1
    $\begingroup$ The effect explained in this answer is correct and the answer is nicely written, however the reason is not accurate. Applying is not telling Blender to create a new reference for easy math - it is actually applying the transformation to the data. $\endgroup$ – Jaroslav Jerryno Novotny Oct 8 '16 at 18:30
  • $\begingroup$ Thank you for bringing that point to debate. Mathematically speaking, when you "apply the transformation to the data", you are basically taking the new dimensions as a new reference frame. You are kind of "resetting" the dimensions and telling Blender that those new dimensions are at the origin (1,1,1) in a sort of "scale plane". Therefore we are saying the same thing: I'm just giving a mathematical explanation of what's going on under the hood, and you are giving the same explanation using Blender's jargon. Have a good day. $\endgroup$ – Jose Lopez Garcia Oct 8 '16 at 19:25
  • $\begingroup$ The scale purpose is not pure mathematical convenience to create a new reference frame. It's purpose is to be able to have multiple instances of same data scaled differently. $\endgroup$ – Jaroslav Jerryno Novotny Oct 8 '16 at 21:53
  • $\begingroup$ Hence the "as far as I know" part. The "new reference frame" is a consequence of the Scale fields, not a whole purpose in and on itself. Thanks again for chiming in. $\endgroup$ – Jose Lopez Garcia Oct 8 '16 at 23:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.