Use of word "Axonometric"

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garya
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Use of word "Axonometric"

Postby garya » Mon Jan 14, 2019 4:37 pm

I'm jumping in way over my head here, but I have a question on terminology in the FreeCAD user interface.
The button for reorienting to the standard skewed view has a tooltip that says "Set to axonometric view (0)".
What it does is set to a quasi-standard skewed view, since it works in both orthographic and perspective view modes.
My (very limited) understanding is that the term axonometric only applies to orthographic views, not perspective ones.
If this is correct, shouldn't these labels be changed to use the term "skew" instead of "axonometric"?
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NormandC
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Re: Use of word "Axonometric"

Postby NormandC » Mon Jan 14, 2019 5:29 pm

BTW axonometric was just renamed isometric in the source code; dimetric and trimeric views were added. https://forum.freecadweb.org/viewtopic. ... 81#p279045

Although you would be technically right, I don't think it would be a good idea to use the term "skew". It would just bring confusion I think. In most CAD programs, the terms isometric/dimetric/trimetric continue to be used even when the projection is set to perspective rather than orthogonal.
garya
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Re: Use of word "Axonometric"

Postby garya » Tue Jan 15, 2019 4:47 am

NormandC wrote:
Mon Jan 14, 2019 5:29 pm
BTW axonometric was just renamed isometric in the source code; dimetric and trimeric views were added. https://forum.freecadweb.org/viewtopic. ... 81#p279045

Although you would be technically right, I don't think it would be a good idea to use the term "skew". It would just bring confusion I think. In most CAD programs, the terms isometric/dimetric/trimetric continue to be used even when the projection is set to perspective rather than orthogonal.
I agree "skew" is not a compelling term. I refrained from suggesting "3D" as the label as it seemed too pedestrian, but thinking about it more I think it would be a better term than anything else. 3D encompasses both orthographic and perspective views. It is accurate and allows for seamless expansion. In orthographic mode, none of the other views are 3D -- they are all 2D projections. In perspective mode, it gives you what you intuitively want when someone asks for a "3D view". An excellent implementation would allow a right click or adjacent arrow to present a popup/dropdown menu which allowed one to select one of the (expandable) set of 3D views; a left click would select the user's choice for a default/preferred 3D view. It would thus easily accommodate the current expansion to include dimetric and trimetric views. Furthermore, doing this would alleviate the proliferation of view buttons in this area, most of which would not be used -- I'm guessing once set, one would seldom switch the 3D view, at least for a given document, although I could be wrong.

As far as "most CAD programs" goes, just because the rest of the world does something incorrect is not a compelling reason to follow suit. This would be a great, albeit small, way for FreeCAD to "do it right" and lead. Mislabeling things inevitably leads to ambiguity, misconceptions, and problems with clarity in the long run.
chrisb
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Re: Use of word "Axonometric"

Postby chrisb » Tue Jan 15, 2019 8:59 am

A fitting german term would translate as "perspective" to English.
GeneFC
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Re: Use of word "Axonometric"

Postby GeneFC » Tue Jan 15, 2019 4:03 pm

garya wrote:
Tue Jan 15, 2019 4:47 am
I'm guessing once set, one would seldom switch the 3D view
I switch views constantly. I don't see how anyone could design without looking at other views.

Frankly this particular issue seems to be "n+1" out of the "n" issues in FreeCAD. :?

Gene
garya
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Re: Use of word "Axonometric"

Postby garya » Tue Jan 15, 2019 7:31 pm

chrisb wrote:
Tue Jan 15, 2019 8:59 am
A fitting german term would translate as "perspective" to English.
Would that be "fernsicht"?
Unfotunately, "perspective" has two possible meanings when used in a freecad environment -- the technical term, where it refers to a specific kind of view; and relaxed general English usage, where it is used similarly to "fernsicht".
IMHO, because of the conflict with the technical term, it is probably best not to use it in this situation.
garya
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Re: Use of word "Axonometric"

Postby garya » Tue Jan 15, 2019 7:57 pm

GeneFC wrote:
Tue Jan 15, 2019 4:03 pm
garya wrote:
Tue Jan 15, 2019 4:47 am
I'm guessing once set, one would seldom switch the 3D view
I switch views constantly. I don't see how anyone could design without looking at other views.
Do you constantly switch between perspective mode and orthographic mode?
Once orthographic mode encompasses three different types, would you constantly switch between isometric, dimetric, and trimetric?
The point is not whether one switches between different views; it is whether or not one switches between different types of "3D" (as in "view from some distance such that you see significant portions of multiple faces of the object") view.
GeneFC wrote:
Tue Jan 15, 2019 4:03 pm

Frankly this particular issue seems to be "n+1" out of the "n" issues in FreeCAD. :?
It's more than just a label. Consider when one is writing a tutorial and wants to say something like "Switch to 3D view."
If the tooltip said "Axonometric", as it does now, one would write the tutorial to say "switch to axonometric view." If the user is in Perspective mode, some users will think, oh, I have to switch to axonometric mode and do that rather than switching to the 3D view. Things go downhill from there. Similar problems arise if one used "Perspective" as Chris suggested -- if one were in orthographic mode, one might switch to perspective mode instead of the 3d/perspective view. The longer you prolong ambiguities / incorrect terms, the more incomprehensible documentation becomes and the more difficult it is to correct.
I prefer Chris's suggestion of "perspective" over the current "axonometric" for sure, as it is correct in the most general sense of the word, and "axonometric," being a purely technical term, is actually wrong. But I think "3D" is probably less confusing overall. I'd be delighted if there were a technical term that were better, although I haven't been able to find one; see 3D Projection.
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NormandC
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Re: Use of word "Axonometric"

Postby NormandC » Thu Jan 17, 2019 4:32 am

garya wrote:
Tue Jan 15, 2019 4:47 am
I refrained from suggesting "3D" as the label as it seemed too pedestrian, but thinking about it more I think it would be a better term than anything else.
I completely disagree. I use "3D view" to refer to the area where the model is shown. I'm sure I'm not alone. An example of use is in Getting_started. Even if you set the 3D view (see what I did there) to a 2D orthographic view (top, right...), it is still a window into a 3D space. Naming this "3D view" would just bring all kinds of confusion instead of bringing clarity.

And what about the three new view orientations: isometric (formerly axonometric), dimetric and trimetric? How would you rename them?

CAD evolved from technical drawing. Technical drawing has always represented objects through orthographic projections. In CAD, the perspective view was added as an afterthought: it's just eye candy. (In the CAD program I use at work, you can't even enable perspective projection from a toolbar or the menu; you need to open a dialog; there's a keyboard + mouse wheel combo that is not documented)

Most experienced CAD users will tell you: they design in orthographic projection, not in perspective. Perspective skews the model to use your words. For example, when you're sketching on the top face of a cube, referring geometry from the bottom face, you absolutely need to have its edges superimposed where they actually are, rather than distorted by perspective.

I would even wager this, I'm surely generalizing but here goes: engineers almost never use perspective projection because they don't see the point (just have a look at the screenshots in the Users Showcase forum). Only architects and industrial designers do, to look at their model in the closest way it will look in real life ;) , or to make screenshots/renders; they return to orthographic projection for design. The time I spend in perspective projection is maybe 2% at most.

Over all the wiki pages you've looked at that contained screenshots, how many show perspective projection? Not that many I'd say.

To me it does not make sense to change the terminology of views to unusual words that will have experienced CAD users scratch their heads, all for a perceived discrepancy that is after all very minor, and only happens marginally.

I mean, you are the first person in 9 years I've been here who's having a problem with this...

garya wrote:
Tue Jan 15, 2019 7:57 pm
Once orthographic mode encompasses three different types, would you constantly switch between isometric, dimetric, and trimetric?
Yes. This is why I've lobbied for it for many years, and finally got my wish! I've already mapped keyboard shortcuts. ;) (7 and 8, as it happens)

garya wrote:
Tue Jan 15, 2019 7:57 pm
If the tooltip said "Axonometric", as it does now, one would write the tutorial to say "switch to axonometric view." If the user is in Perspective mode, some users will think, oh, I have to switch to axonometric mode and do that rather than switching to the 3D view. Things go downhill from there.
Uh, sorry but "I have to switch to axonometric mode and do that rather than switching to the 3D view" makes no sense to me.

In any case, I very much doubt that a beginner will ever have that thought. For one thing, they won't even know what an axonometric view is, so we'll have to explain it, or link to the command page. And, they will probably not even know yet that they can switch to perspective projection. AFAIK there is no mention of it on the wiki, and orthographic view is the default.

If you insist on this, we could always add to all the tutorials on the wiki to make sure to start in orthographic view.
Last edited by NormandC on Thu Jan 17, 2019 5:14 am, edited 1 time in total.
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NormandC
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Re: Use of word "Axonometric"

Postby NormandC » Thu Jan 17, 2019 5:00 am

Links for further discussion, not directly about axonometric, but related I think...

http://help.solidworks.com/2019/English ... 8fa56f#Pg0
They refer to what I call the "3D view" as the "graphics area".

https://support.ptc.com/help/creo/creo_ ... ow.html%23
Creo refers to the "graphics window".

In a very old Solid Edge user's guide I have at home, they refer to it as the "working area".

I will concede that ceasing use of "3D view" to label the area where the model is shown, and finding a different term for it may be a first step in reducing confusion.

Links about views...
http://help.solidworks.com/2019/english ... 1fcbeb#Pg0
http://help.solidworks.com/2019/english ... 2dto3d.htm
http://help.solidworks.com/2019/english ... d4e48a#Pg0
https://support.ptc.com/help/creo/creo_ ... ation.html
chrisb
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Re: Use of word "Axonometric"

Postby chrisb » Thu Jan 17, 2019 7:02 am

When writing about Sketcher I asked how to name what ended even there in "3D view". There were no complaints although it's rather 2D. Naming it "Graphics view" seems very sensible to me. I don't like "Working area" because therea are many situations where I work rather in the panel to the left by editing values than working in the 3D view.