Lecture 37. This was confusing, I think I need a Guinness

[Derek_O_Reilly]

I’m very confused, trying to simplify what was said in the lecture.

From 3:30 mins He says something like:

In object mode if we rotate the cube to 45 degrees around the Z axis and then rotate a small bit on the Y axis we see that the cube will be a lot more than 2 blender units across, but it’s still reading 2.000 x 2.000 x 2.000 on the dimensions section in the properties panel.

Now Just to clarify, is this his what he was trying to say?:

If I had a box that stood lets just say 3 ft high by 2 ft wide , but then I decide to place it on a table top that measured lets say 6 ft by 6 ft, well then we automatically know that 2 ft of that table is being covered by the box. But what if we decided to topple the box over so that the Box is now lying on its longer side, then you will see that the box although filling more area on the table because its 3 ft length is facing down on the table doesn’t mean that the box has changed size or dimension, its still the same sized box, and the table is still the same sized table, now if we apply this example to the cube in blender when it is in object mode only and before scale rotation and location are applied then we see that the dimensions refer to the objects dimension relative to itself, basically the boxes size and shape are the same, But when location, rotation and scale is applied, it refers to the area on the table that has been covered by the object, was this what he was getting at ? I am probably talking a load of rubbish here but just trying to get this right in my head.

So just for laughs, an objects dimensions and the area it covers are 2 very different things but yet are sum of there parts, for example a UPS driver is not interested so much in the dimensions of a box, but more interested the how much space it will occupy in his van , but if the van driver considered box sizes alone without taking the area it covers in to account then before you know it you have yourself a very difficult game of tetris on your hands.

I bet you I still haven’t gotten it right, LOL, as thick as farmers welly me. Oh well.

My brains on fire, I need more than a Guinness now, Well I am a Paddy after all, what did you expect? LOL.
Anyway it’s no harm, these lecturers have us really thinking, I like that a lot and they are keeping us all on our toes, getting us to think about things in a different way and being out of our comfort zone is a good excercise.

[FedPete]

Objects in Blender use a radius. For me this is, was also confusing. A cube doesn’t have a radius, but in blender it does.
So if radius is one, the dimensions will be 2.

Then the object by it self has different properties (scale, dimension, rotation …) as the inner parts of the object, exciting of vertices, edges, faces. It’s difficult to explain, but it will be explained to you in the following lessons.

For example you can have a rectangle box, scaled on the x-as to look like a real square cube. But for the maths in Blender, it isn’t. You’ve applied a scale modifier on the x-ax on a rectangle box.

You will get there at the end, don’t give up
I’ve been there … you’re not alone !
Happy rendering.

[Steve1222]

I was very confused at first. But it think what hes trying to say is that, when you rotate an object in object mode, the mesh vertices are unaltered and the dimensions reflect the actual model dimensions, not the appearance of it in in your scene. If you’d like the mesh to be rotated like this by default, you can apply the rotation change with shortcut ctrl+a.

However if you rotate your object/vertices in edit mode, it changes the actual object and so the dimensions are accurately reflected.

Irrelevantly, there is also a shortcut to automatically enter 0 into all your values with the clear command, of which there are also shortcuts for.

Why he made this sound so convoluted instead of a simple side note? Perhaps he didn’t think this through enough, forgetting we need to move on and continue learning instead of our ship getting damaged by tiny icebergs

[Steve1222]

He hasn’t covered much on origins btw, do you guys know how to move it? my origin did change from applying the scale

[Dodi]

This is how I understood it, Before rotating and every transform, compare the cube to the x axis for instance, that face is 2 blender units wide.

after rotation, it looks wider than just 2 blender units
try it in orthographic projection, it worked for me, but God I feel stupid… is this right?

so its like dimension concerning the x axis is 2 units but when rotated it’s different, the dimension of x didn’t change cause he didn’t apply it.

So when you rotate this over the y axis on 35 degrees, so it lies on the x. you see now after applying it the x dimension becomes √12 which is 3.464

Let’s see the Pythagoras theorem.

Now don’t look at the top image, look at the bottom one. √12 Follows x axis. and this is why the dimension of x is 3.464

I was confused too… but I applied this in order to understand it I hope this helps and i’m no math expert I just wish they edit this lecture to make it easier to understand…

[Jamie_R]

Just adding another voice but I also found this one really confusing. Sometimes its like hes about to teach you something important and then goes off on a bit of a tangent and you kind of don’t really know what the original point he was trying to get across is?

I’ve watched it 2/3 times now and I think he is just trying to get us to consider that until a transformation is actually applied, the dimensions given refer to the object’s condition pre-transformation. Any scale/rotation/location values can be considered a temporary effect rather than actually modifying the cube.

But… I don’t feel sure at all and I hate moving on without feeling like I have learned what I was supposed to learn