Left hand and right hand coordinate systems

My first thought is that you are coming from some other system that requires you to establish the coordinate system first. In SW, you can just put the stuff where you want it.

If you want to do this in a part file, start your part on the desired plane, and then reset your standard views to make "front" look like you want it. If you want this change in an assy, mate the parts to the system planes and reset the standard views such that the "front" view looks like you desire.

WT

SW doesn't striclty follow a right hand rule.

What are you trying to do?

Solidworks is set up by default to the Right Hand Rule, I want to set up a coordinate system in the Left Hand Rule.

Why do you want a left hand rule? I am asking because SW won't let you do a LHR, but if we knew what you were trying to do we might have another solution (workaround).

I need to get XYZ coordinates and under the right hand rule my Y coordinate is a positive number and it should be a negative number for this particular project. Aircraft traditionally have the X positive axis running along the length of the fuselage (station) towards the rear, The Z axis positive points upwards (water line) and tha Y axis is positive on the port side (LHS looking forward, Butt lines) The Right Hand rule does not follow this convention.

0,0,0 is at the front of the aircraft. This is not a biggy as I can of course change a negative number to a positive number, I was just wondering if it was possible to get setup correctly for the Left hand rule convention.

Curiosity question: What are you going on (referencing) re usage of the left hand rule?

I doubt this of much use, but was "thinking" (and it Is difficult) that ...

I don't think there is a tradition, just company conventions (?). Seems that ...

Boeing X = aft, Y = rt, Z = up MD was X = aft, Y = up, Z = lt (based on models from a friend of a friend of a...)

It's amazing how hard it is to get info re the subject. Guess if you know someone in factory engineering departments...

I know I've seen some discussions re the subject that may or may not have been accurate. A web search turned up

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(I don't use SW, sorta grasping for straws...) Is sign (+/-) important? Will planes defined by three points (should allow plane x, y, normal per your requirements) help? I have gotten around coord sys orientation problems for things like exports by nesting the top assy in a new assy, orienting as required and writing out from there. That's a simple transform, don't think it will help if there is a "handed" issue ....

Sorry to just contribute to confusion, but am curious about the left hand rule application.

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In a SolidWorks part or assembly file the user can create one or more coordinate systems in addition to the default World Origin and X,Y&Z axes (using Insert/Reference Geometry/Coordinate System from the Main Menu).

Such alternate coordinates will NOT allow sketch and feature dimensions to be driven in new directions (relative to the defaults); however, if the file is exported, the translation can optionally specify a user defined origin and axial directions to reposition, rotate and flip the output geometry.

Per O. Hoel

There you go again. One of those bloopers just over the infielders' heads. I look up, it makes me dizzy. Are you saying there is a correlation between first and third angle projections, left-hand and right-hand rules or, maybe, that those that use first angle projections tend to define coordinate systems using a left-hand rule? I'm from Texas. I don't know. ...

I can grasp plane / face normals being defined by left or right hand rule and guess it's just another step or two to define a coord sys by left hand rule (?), I've just never used a program that would allow either (for what little that's worth). ... Trying to picture it. Start with a BL plane, x aft, y up, normal to A/C left side per R/H rule, to A/C right side per L/H rule. ... I'd have to ponder on it for hours, probably just confuse myself. Is this rocket science? It's late and I still have a lot to do. Maybe another day. `;^)

Wonder what Airbus uses for body coord sys?

Professor TOP here,

First and Third angle projections have to do with the relative location of the object, viewer and viewplanes used for making multiview orthographic projections. Coordinate systems don't come into play. See Bertoline, "Technical Graphics Communication", p396ff. A first angle projection should really be called a first quadrant projection.

In first angle projection the view plane is on the opposite side of the object from the viewer. In third angle projection the view plane is between the viewer and the object. In first angle, the right side view must then be positioned to the left of the front view and the top view below.

This "simple" rule to remember the Right Hand Rule from the left requires that you remember the order of Cartesian coordinates is X, Y, Z and that you have a hand with at least on finger and a thumb. For RHR place your hand so that your right hand finger(s) curl around the Z axis such that the finger points in the direction that would rotate the X axis into the Y axis The important thing to remember is that Z comes from curling the right hand fingers from X to Y, X comes from pointing the fingers from Y to Z and Y comes from pointing the fingers from Z to X. If you substitute the left hand you will find Z goes in the opposite direction while X and Y can remain the same. .

Hi Jeff, modern CAD designed aircraft do follow the Right Hand Rule, but this was the OEM's changing their sytem to suit CAD. Older pre CAD aircraft use the Left Hand Rule.

Ah! Thanks, Phil.