I am really excited to have Jaiprakash Pandey share with us some of his immense knowledge of AutoCAD! Once you have read this article, please head over to his blog SourceCAD for a tonne of really useful articles, hints and tips on all things CAD.
Managing coordinates in AutoCAD 3D
In AutoCAD, you can only draw on XY plane and this restriction has little impact in the 2D workspace but when you move to 3D all hell breaks loose. In 3D space the drawings need to be drawn on many different planes some are predefined planes like XY, YZ or ZX and others are user-defined planes.
To make a drawing on any plane you need to rotate the user coordinate system (UCS) to the desired plane so that XY becomes the plane on which geometry is to be drawn. There are plenty of tools available on Coordinates panel of the home tab that can make this task easy.
In this article, I will explain most of the coordinate tools which are very frequently used to manipulate the UCS.
View drop down menu:
In the image below we have a 3D geometry with planes of different colour, let’s assume that we want to make a geometry on the grey plane of this 3D shape.
Currently, the UCS is aligned to the default XY axis which is perpendicular to the grey plane. Select Face option from the View drop-down menu as shown in the image below and click on the grey plane of the 3D geometry and press enter. Your UCS will now align with the grey plane making XY axis parallel to the grey plane. Now you can make any geometry on the selected plane.
To return back to the default state of the UCS click on the world icon on coordinates panel.
There is also another approach which can be used to rotate the UCS direction to align it with a plane. For that, select the respective plane from view cube so that the complete geometry rotates to that view and then select view option from the drop down menu mentioned in the previous case. The XY axis will orient to the view in which your drawing is rotated.
In this case, also you can click on world icon to return back to the default state of UCS.
If you have any existing 2D geometry in the drawing area and you want to align the XY axis of the UCS to the plane of that 2D object then simply select the “Object” option of the view drop down menu and click on the existing object on the drawing area. The XY plane will align with respect to the existing 2D geometry.
Aligning UCS on an inclined plane:
In the 3D object shown above the plane mentioned in red colour is not parallel to any of the planes of view cube, in order to make an object on that plane you need to align XY axis to that plane. The 3 point tool can be most efficiently used in this case to align the UCS with respect to the plane.
Select the 3 Point tool then click on any one of the vertexes of the slant plane to specify the origin of UCS. Now click at a second point on the plane to specify the direction of X axis and then specify the direction of Y-axis perpendicular to the X-axis but on the slant plane, as shown in the image below.
The UCS will align with respect to the red plane and the geometries can now be drawn on it.
Moving UCS on the parallel plane:
You can use “Origin” tool of the coordinates panel to move UCS on parallel planes. In the sample 3D drawing, we have two parallel planes marked with Yellow and Green colour. Let’s assume that our UCS is on the green plane in such a way that XY axis is parallel to it and we want to move the UCS on Yellow plane without altering the orientation of axes. For that, select Origin tool and simply click on any point on the yellow plane and the UCS will be placed on it.
There are also many other AutoCAD commands related to the coordinates which can be used in different circumstances, but these were the most frequently used tools.
About the Author:
Jaiprakash Pandey is a Mechanical Engineer currently working as CAD Corporate trainer. He is an Autodesk AutoCAD certified professional and an Autodesk expert elite member. He provides training in AutoCAD, CATIA and other CAD products to corporate clients. He is a regular contributor to AUGI world magazine and he also develops AutoCAD video courses for Pluralsight and his own platform SourceCAD. You can reach him on his blog SourceCAD.