How does axes work when I want to import .obj file into scene ?

This theme are doing me confusing. I tried do this lesson https://cgcookie.com/lesson/importing-objects

And it doesn't work for me just like in video. 

1. The same settings:

2.as a result we have difference with axes(axis)XYZ:

I'd like to know how this axes work. any links will be good. 

P.S Guys, I'm really apologize for my English.Its,  I try to learn it too.

  • Hello Daniil, I can see how that confuses you.

    This difference in axes comes from the fact that the Bulldozer.obj file that is used in the video is different from the Bulldozer.obj that is in the source files that you've downloaded.

    You can see that the file size is different, but also the orientation of the axes is different.

    To get the model to stand up straight, you would need to import it with Y forward and -Z up.

    So, you didn't do anything wrong, it's just a different model.

    I hope this clears it up a bit.

  • spikeyxxx thanks for reply sir. It  works with yours. But:

    I don't understand how axes turn. It seems so strange for me.

     I'd like to understand  logic of axes turning. I always ask myself why it's so!?? I think I need to come from smth in my head, but I only know that in bledner: 

    (x is  right; -x is left) = width of object. (y is back; - y is forward) = depth. ( z is up; -z is bottom) = height 


    My stages of working on it:

    1. Import any object in blender and set settings such axes as must be in blender - Y forward and Z up, in order to check that on correctness of sides.

    I get the next: 

    My analysis:

    My goal is to turn the roof up z and the tractor bucket forward -y.

    Axes of this .obj are next  -z are top, forward is -x.

    2. I tried to get the tractor roof up; set UP: - Z

    and get next.

    I don't understand why this tractor turned its bucket to X ? 

    I expected next picture:

    I don't understand how it rotates. I want get the next:

    Please help me how it works? logic behind rotation of obj when I change axes.

  • ddanny You will have to know how the axes of the Bulldozer are. In order to see this, you need to select the Bulldozer and change the (axes-)Gizmo from Global (which show the Blender world axes) to Local ( which shows the selected object's axes). You find this at the bottom of the 3D Viewport, left of those 10 little squares(the Layers).

    If you then set the -X (of the Bulldozer!) to be forward and the-Z(again, of the Bulldozer) to be up, you should get what you want.

    If you import your own model, you should already know the model's axes.

  • ddanny As for the why and how, you might want to look into something called 3D math or Vector math.  3D math is a little complicated, but worth understanding.  I have only ventured a little into it, but I can tell it will take repeated reading, learning, and application to get comfortable with the concepts.  You don't have to know it necessarily, but it would certainly help to augment your understanding, just like you don't have to know how an engine works to drive a car, but it certainly helps to narrow down what's wrong.

  • silentheart00  got it. Thanks mate. I gonna learn 3D math:)

  • spikeyxxx thank u sir! Problem was in my misunderstanding of what I needed to use LOCAL!  axes. I got this theme.!!!

  • ddanny 👍 Power to you!