ZX plane in PartDesign Next (instead of XZ)

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galou_breizh
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ZX plane in PartDesign Next (instead of XZ)

Postby galou_breizh » Sat Apr 16, 2016 6:14 am

There were some discussion about extrusion done from a sketch in the XZ plane going actually into the -Y direction in the old PartDesign workbench. This is solved now in the PartDesign Next workbench.

However, in my opinion, there is still an inconsistency in the plane name. I would prefer personally to name it the ZX plane instead of XZ, for mathematical consistency. This is maybe not what is used in other CAD softwares but do we really care?

My argumentation is:
cross(X, Y) = Z
cross(X, Z) = -Y
cross(Z, X) = Y
cross(Y, Z) = X

What do you think about it?
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NormandC
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby NormandC » Sat Apr 16, 2016 6:24 am

galou_breizh wrote:There were some discussion about extrusion done from a sketch in the XZ plane going actually into the -Y direction in the old PartDesign workbench. This is solved now in the PartDesign Next workbench.
You call that solved? I call that a bug :D

viewtopic.php?f=10&t=15207&start=40#p121522

Seriously, I really hate it. It is much more logical if you want to create a sketch on the "front view" (XZ plane) that the normal vector would be (0,-1,0). :|
ickby
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby ickby » Sat Apr 16, 2016 7:22 am

I remember that we discussed this during initial development and chafed it to current behavior, but I can't remember why :) honestly I'm personal very indifferent to this, I have no opinion what is better. Itncan easily be changed
galou_breizh
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby galou_breizh » Sat Apr 16, 2016 1:17 pm

I actually agree with you Normand. The normal of the XZ plane should be -Y and the normal of the ZX plane should be +Y. The question is which one should we presented by default. As you understood, I would prefer the ZX plane.

Whether of not it can be easily changed, I think now is a good opportunity to find a consensus.
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DeepSOIC
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby DeepSOIC » Sat Apr 16, 2016 2:17 pm

I want the old XZ plane with extrusion direction of -Y. I think it makes most sense to have sketch axes directions same as global axes directions. Currently, X sketch axis is against global X axis, which is kinda funny.
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nemesis
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby nemesis » Sun Apr 17, 2016 7:02 am

DeepSOIC wrote: I think it makes most sense to have sketch axes directions same as global axes directions. Currently, X sketch axis is against global X axis, which is kinda funny.
IMHO axis in the sketch should have a different name than main axis (such as u,v) as its a local axis, and not always parallel to main axis.

But now with the "Map Reversed" Property, that's easy to switch the normal, within the sketch, that's not a fundamental problem. maybe a global preference to let users choose the default comportement should please very one. I don't think that's a high prior feature lol.
NormandC wrote: if you want to create a sketch on the "front view" (XZ plane)
that's where a cross field software as freecad has its limitation. Architect, Mechanical Engigeers, and Body in white designer don't share the same Front view.
for me the front view is the YZ one, the XZ is the Elevation, and XY is the mass plan. so maybe at the end a global user preference make sense.
nzurbrugg
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby nzurbrugg » Mon Apr 18, 2016 4:56 am

For what it's worth, catia names it "ZX plane" instead of "XZ plane". I'm biased since I'm a catia user, but I find ZX easier to work with since you only need to look at the first letter to find which one you're looking for:
  • XY plane
    YZ plane
    ZX plane
vs
  • XY plane
    XZ plane
    YZ plane
But that seems trivial compared to the mathematical reason :-)

For the view schema, catia is also a bit different:
  • front/rear: YZ plane
    left /right: ZX plane(or XZ)
vs FreeCAD:
  • front/rear: XZ plane (or ZX)
    left /right: YZ plane
Catia's view schema fits more naturally with the automotive world since the standard convention is to use the ZX plane as the plane of symmetry of the vehicle (and I believe this is true for aircraft as well). Then when you click the left-view button, it shows the left side of the car (ZX plane). However... when you click the FRONT-view button, it shows the REAR of the car! So it's still not completely intuitive...
jmaustpc
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby jmaustpc » Mon Apr 18, 2016 12:24 pm

nzurbrugg wrote:For the view schema, catia is also a bit different:

front/rear: YZ plane
left /right: ZX plane(or XZ)

vs FreeCAD:

front/rear: XZ plane (or ZX)
left /right: YZ plane


Catia's view schema fits more naturally with the automotive world since the standard convention is to use the ZX plane as the plane of symmetry of the vehicle (and I believe this is true for aircraft as well). Then when you click the left-view button, it shows the left side of the car (ZX plane). However... when you click the FRONT-view button, it shows the REAR of the car! So it's still not completely intuitive...
Hi
I think you will find that this viewing direction is a regional setting in Catia...in the old hand drafting days it was first or third angle projection, depending on your country/region. Are you in Western Europe some where? There was some discussion about changing this in FreeCAD or better still making it an option, but we decided to leave it the way FreeCAD has always been as this seemed to be the most common default that more people were used to and also because either way would bother someone or other so leaving it the way it was seemed the best for that time. If someone wants to write the code, then making this optional could be a good idea.
nzurbrugg
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby nzurbrugg » Mon Apr 18, 2016 1:29 pm

jmaustpc wrote:Are you in Western Europe some where?
I'm in the US. Which might explain my lack of regional awareness ;-)
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DeepSOIC
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Re: ZX plane in PartDesign Next (instead of XZ)

Postby DeepSOIC » Tue Apr 19, 2016 6:01 pm

I'm busy reversing the plane. I found the place where it is set, changed it, and if it works, you'll see a pull request soon.