When you are drawing in isometric mode, you add schematic symbols on one of the 3 isometric planes: left, top, or right. Each isometric plane has an associated pair of axes. Choosing an isometric plane causes the AutoCAD® Ortho mode and the crosshairs to be aligned along the corresponding isometric axes in the world coordinate system (WCS). Working in isometric mode is beneficial, for example, when creating electrical riser diagrams.
As you draw, you can switch between planes by selecting a different value for Isoplane on the Properties palette. Switching between planes enables you to continuously add end-of-line or in-line symbols on the different isoplanes. For example, you might add one symbol on a line on the top plane, switch to the left plane to add a symbol on a riser, and then switch to the right plane to add an end-of-line symbol to complete the run.
Adding a schematic symbol to the left isoplane
Adding a schematic symbol to the top isoplane
Adding a schematic symbol to the right isoplane