Are the front and back orthographic views backwards?

General Forums Blender and CG Discussions
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This is a tough one to be sure about, as I know there are many different standards, as well as some “arbitrary choice” associated with this, but, I’m of the opinion that the Front and Back views are “backwards” in Blender.

This is what I understand.
Blender uses a Z-up Right Hand coordinate system. This corresponds with many standards for engineering and mathematics, but is not a “hard and fast rule”.
Some other programs use a Y-up Right Hand coordinate system, still others use a Y-up Left Hand coordinate system. In the end none of those choices really matter as once you pick a reference, all the math is the same in the end.

Regardless of the system, it seems to me that when I choose a view by “name”, in blender, the view name should relate to what part “of the object” is being shown from the 3D view.

For instance, if we “choose” the RIGHT view to be looking at the object from the positive x-axis (looking at the right side OF THE OBJECT), that would indicate to me that the TOP view should look at the object from the positive z-axis (looking at the actual physical top OF THE OBJECT), and therefore the FRONT view should be looking at the physical FRONT OF THE OBJECT, down the positive y-axis. As it stands now, the FRONT view seems to look at the object from the negative y-axis and thus looks at the BACK OF THE OBJECT.

It’s hard to understand if you use just a cube, because there is no designated “front or back” for a cube, but if you place something like a character in the 3D view, and you line the characters “right hand” to the “right view”, and the top of the characters head to the “top view”…the front view shows his BACK.

I also tried three other programs (Silo, Hexagon, and Lightwave), and 2 of the 3 work as I would expect them to (front, right, and top line up with the “positive” axes, and the view names correspond with the objects sides). Even though both Silo and Lightwave use a y-up right hand coordinate system, they work as expected, it’s just that objects are rotated 90 degrees on the x-axis in those programs, compared to Blender.
Hexagon also uses a y-up right hand coordinate system, but it too seems backwards, in that they choose the front to point down the positive z-axis “but” when you look at the right view, you see the object from the “objects” left side. For Hexagon though, I guess this may come from them saying that if you’re “looking” at the object sitting at the at the origin, the right side of the object would be on “your left”. Blender, however, doesn’t even seem to make sense that way as the back and front views are reversed.
This obviously causes problems with orthographic projection references.
For instance a 3 view reference schematic of a car would show the front, right, and top “of the car”, and therefore it would be backwards in one view (either front and back or left and right) if imported in all views in Blender.

Here’s a link to an example, the names of the views correspond with the “object” not where it is viewed “from” (or whatever it is Blender is based on).

http://www.tech.plymouth.ac.uk/dmme/cad/ortho.htm

The two images on the right and left side of the page of the little bue house show what I’m talking about.

Seems backwards to me.
Thoughts?
Maybe a change/fix for 2.5?

2

The ‘Right’ view in Blender means from the right-hand side of the scene (looking at it from the front), not the right-hand side of any particular object. If an object is facing forwards, the left of the object is on the right of the scene; conversely, if an object is aligned so that its right is on the right of the scene that object must be facing backwards (assuming its top is up).

Best wishes,
Matthew

3

Well I see the rationale now at least, however, I still disagree. Orthographic views are generally for modeling. In fact, I can’t think of a single time that I wanted an orthographic view relative to a scene relating to “my right”.

When I go look for reference images to place in a view background, I don’t think to myself, “hey, I better get a left side view to place in a “right” orthographic view, or a “back” view to place in the front ortho view”.
If I’m building a scene with a house and characters, I would place the house facing front and expect the right side of the scene to be relative to that house that is in the scene and setting the scene direction.

By doing it this way it also forces two thought references, first the object placement front, then “my right”. Let alone, I’d generally say I want the front and top views to orient to the “positive” axes, as when I translate an object numerically I don’t want to be thinking to myself, now is this a “positive or a negative to move the object forward?”. Right now, one axis always has to be negative relative to the object I’m moving.

I’m sure there’s some room for debate here, but it’s always been my impression that choosing a standard should be pretty consistent. Referencing the coordinates to how the user “looks” at it, rather than something non-negotiable and unchanging (the objects right and left and front and back), doesn’t seem the best way to go about it, nor does it conform with “orthographic projection” which has been done to show 3D objects as 2D images for hundreds of years now.

4

when you look at the front view port
it’s the front view but if you Ctlr-1 you get the back
like if your where looking through a camera and changing it’s location from front to back
the camera goes from the front of the scene to the back of the scene and rotate 180 degrees around the Z axis - so everything gets inverted around z axis
what was on the right goes to the left ect

ounce you get use to the sytem it’s very simple and always the same inside blender
but other soft migth be doing something else!

hope it helps

Salutations

1 Like
5

Thanks, I understand it just fine, it just could be done the “other way” and still conform to a standard and be more consistent by not referencing right to something “external” to the scene (window/camera/my view). By using “my right” as the reference, it changes depending on how I view the scene and also doesn’t conform to orthographic view projection.

Using your example, if I look at the scene from the front, then the right side is on “my right”, so yes when I switch to the right view you can think of the camera rotating 90 degrees around the z to the right view. Fine.

The problem is, let’s say I view the scene from the back, the right side of the scene (according to Blender) is now on “my left” which means the reference I used before has now changed. Now I’ve had to use two different references (my own changing ones) to determine what the “right side” of the scene is.

Doing it the conventional way, the right side “of the scene” is always the same, no matter how “I” choose to look at it. I place an object facing “front” and I make the front the positive y-axis, the right is now the positive x-axis, and the top is now the positive z-axis, relative to the object facing front (or it could even be negative x, y, and z). Now when I rotate around the scene, the right side “of the scene” is always the same as referenced to the objects “in” the scene (that make up the scene) and my “changing” view is never part of the thought process of what is the right side, left side, up, down, etc. Also now everything is referenced to the axes in the same way (not two views to positive axes and one to a negative axis), and the views are “named” in a way that relates correctly to orthographic projection.

Edit: I thought of another way of looking at it.

The orthographic views should always show me what the camera “sees”. Currently, four of the six views do this, two others do not, so therefore the system is inconsistent.
Example:
Make a character and place him at the origin with his front side facing the “front view” (which is currently the -y axis).
If I pretend I’m the camera looking at the character, when I go to the front view, it should show me the character’s (the scene’s) front, and it does.
What would also make sense is that the top view should show me the top of the character (this is how I know it’s the top view, and it will if you put the character in upright, head pointing toward the +z. If you did it backwards you can just rotate the character and fix it.
Now for the other views things also follow the same standard (the view shows what the camera sees).

Top view —> Shows the top of the character, looks down +z
Bottom view -----> Shows the bottom of the character, looks up -z
Front view -----> Shows the front of the character, looks down -y
Back view -----> Shows the back of the character, looks down +y

Now the problem comes in. According to blenders view navigation, when I go to the right view, using the four other views above as a reference, it should show me what the camera would see (the right side of the character), when in fact it shows me the left side.

Right view ------> Shows the left of the character, looks down +x
Left view -------> Shows the right of the character, looks down -x

So basically a different standard for two of six views, and one of the primary views is along a negative axis.

If I rotate the character to fix the right and left views, now the front and back are off.

6

in blender ortho is more a special case than anything else -but is’s available

in the web Site given showing the 2D dwg for ortho
usually in industrial dwg your drawing represent one object
so the object is the model so ortho mode is defined by the view for this object

but in blender it’s a lot more than one object it’s a complete scene with several objects
so you cannot really think of one object you must think in terms of the whole scene with several objects and the camera looks at the whole scene not one object nornally

now if yo want to see one object then select that object and go into local mode
with Keypad \ key - then you have only one object and you get the same orho mod then
the Pic shown in web site
on keypad you control ortho / perspective mode with 5-Key

also blender is not a CAD soft it’s more a general but 3D modelisation soft
for organic or artistic things - mechanical things come as last on the list
the tools are there and new ones will come in the next release

so get use to this way cause i don’t think it’s ready to change to be a CAD soft !

good luck

7

Thanks, I guess I can use local mode, however that doesn’t help when modeling one object “relative” to another object in the “scene”.
Therefore, my point still stands, you could make the world system use the same same system as the local mode…then you might not “need” a local mode, other than to see objects one at a time and when you switch methods it would be consistent.

I guess what I don’t understand is why would I think of the “scene” any differently than the “objects in the scene”?
Up, down, front, and back of the objects in the scene determine which way the scene is facing, why not left and right too?
You’ll always need local and world coordinates to handle the rotation of objects relative to each other (relative to the whole scene), but why choose two different standards? It makes no sense to me.

It just seems to me that if I make a scene with a bunch of people waiting in line for tickets and I want to see their tops (the tops of their heads), I’d choose the top view, if I want to see their front (their faces), I’d align them so they face the front view and choose the front view. Therefore, logic would dictate that if I want to see their right sides…I’d choose right view…but that’s not the case based on the system in place. The characters “are” the scene, the objects “are” the scene, no matter how many of them I have.

8

Hm you want to switch to back view each time you work on the front of the character even if its the most important/detailed part of it? What a waste of efford and time. Its not a mirror and also not a third person shooter or a arcade racer.

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I’m not sure I follow you, what defines what the “back view” is, where I’m watching from, or what part of the objects I see? Right now blender shows me “what part of the objects I see” in 4 views, and “where I’m watching from” in 2 views.

I want the front of the character(s) to show in the front view, and the right of the character(s) to show in the right view, and the top of the character(s) to show in the top view, unless I choose to face a character in an opposite direction, in which case I know that one is backwards relative to the majority of items in the scene. I want the orthographic views to show me what the “camera would see” and I want the views to be consistent and standardized on positive axes.
I’d also argue that if i use blender as a game engine, it “is” a third person shooter or an arcade racer. Why have two opposite ways of looking at the same stuff?

10

when you look at your screen you normally see 4 screens
i mean if you go that way

now in blender you have the world which is everything with it’s main axis

but if you look at the top bar you can select different scenes
in one blender file you can have several scenes with lots of objects for each scene

so you have a choice for the viewport to show whatever side you want
top bottom front back rigth left but all theses are referring to the world axis

and it happens in blender that the positive x axis is on the right so that’s the right by definition in blender

now agreed that in other soft it may not be defined that way !

but that’s life not everybody does things the same way - not everything is described in a proper scentifique way - many times in blender you’ll find physicals description other times it 's more an artistic description

but i’m cetain ounce you get used to it you want event think about it and you’ll simply enjoy it

happy blendering

11

if you’r not certain about the view you have in a viewport
you can tell blender to show the name of this view

go to your user preferences and set the name for viewport
so if you click on keypad 7 it will show at the top left the name " Front view " of the view

so that way you can always tell which sides your looking at
and this is always refered to the world coordinates

hope this can help you know determine which view you’r looking at in blender

Happy blendering

12

I appreciate the enthusiasm Ricky, and actually, I have gotten “used” to it and use blender quite a bit, in fact, I’ve been using blender in various capacities, for many years now. However, every time I look at it, it’s still backwards to logical convention, so I was hoping others might see the advantage of change. Regardless of whether I get used to it or not, the fact is, the “local views” of an object will not match up with the “world views” of an object for the vast majority of objects if I choose to align them to front in the world view. This seems counter intuitive to me, regardless of how “used to it” I am.
When doing it the “blender way” if I rotate out of the front view, 90% of the time I’m looking at the “back” (negative side) of the 3D manipulator, but if I rotate out of the right and top views, I’m looking at the “front” of the manipulator.
Doing it the conventional way would put the rotation out of the view facing the front of the manipulator, in all views, in 90% of cases, the smaller percentage being for objects that intentionally placed upside down or backwards “in the scene”.