Create new Symbols for Isometrics in AutoCAD Plant 3D

This entry is part 3 of 4 in the series Custom Piping Components - Plant 3D

A while back we walked through creating a custom symbol for a Plant 3D model.  Today we are going to extend our customization to include a symbol for the iso.  We will create a symbol that shows up in the bill of material and one that does not.

First a little bit about the way symbols work.  AutoCAD Plant 3D has a list of predefined symbols that are used in its isometrics.  Each of these symbols belongs in a symbol category. P3D changes information related to the symbol based on the category.  So the trick will be to use different categories for our symbol.

For those of you who are familiar with Isogen, pretty much everyone has a strong dislike for the symbol editor.  Thankfully, symbols for the P3D package are blocks, so they are easily editable through AutoCAD.  Also, since symbols are stored in a drawing file, we are able to read them and create documentation. Below is a link to download a pdf of the default symbols in P3D.

Creating Custom ISOGEN Symbols (385 downloads)


We are working on a tool to allow creating the html file automatically so you can easily document what symbols are used in a project.

Here are the steps we will use to create a new isometric symbol.

  1. Create our block in the Isometric symbols drawing (IsoSymbolStyles.dwg).
  2. Add our Symbol to the symbol key map file (IsoSkeyAcadBlockMap.xml).
  3. Add our symbol information to the catalog information and/or components in the model.


Creating our Symbol Block

So, first we will create a new symbol in our symbol library file.  Our first symbol is going to be a pressure indicator that will show up in the Bill of Material.  Open project setup and go to Isometric DWG Settings > Title Block and Display > Edit Isometric Symbol


Enter PressureIndicator for the block name to create and click Ok.


Draw a line starting at 0,0 and going to the right 1 1/8”.


Draw a circle with a 1 1/8” diameter with its right tangent at the origin.



We are going to be using the MISC-COMPONENT group for our Pressure Indicator. Currently, the dynamic points are not recognized in blocks for the miscellaneous group, but we are going to add them anyways.

Click the point parameter insert button.


Create a point parameter at the end of the indicator and call it Port1.


Create a point parameter at the end of the bubble and call it Port2.  Add a point parameter at the origin and called it CP.  I got the idea from looking at other symbols and seeing how they were created.


Again, the block will be inserted correctly without these parameters; I recommended including them as a way of possibly future-proofing the block.

Close the block editor, saving the changes.

That is all that is necessary to create our new symbol! The next steps will walk through modify the setup so that we can use the symbol in our isometrics.

Adding our Symbol Information to the Setup

In Windows Explorer, navigate to your project folder\Isometric and open the IsoSkeyAcadBlockMap.xml.  You can open the SkeyMap in Notepad or a good XML Editor. Right now I use TotalEdit or XML Notepad.

Add the line:

<SkeyMap SKEY=”PI??” AcadBlock = “PressureIndicator”/>

I added it after the spacer, but order doesn’t matter.  It’s just helpful to keep similar items grouped if you are looking for something.


A quick note about xml. A line surrounded <!- – and – -> indicates a comment.

You will notice that we used PI??.  I chose to start our new key with PI because we are representing pressure indicators. The “??” means that the symbol will have the appropriate end type symbol added to it based on the connection type.

Quick shout out to Damian, who probably never realized this xml would get read in public! Smile

Save the file and close it.

Now that we have added our symbol to the project setup, we can reference it in our catalog or models.

Add symbol information to the Catalog or Model

The best way to check out if our symbol works is to place a component in the model and change the information being assigned to it. I have a couple copies of our pressure indicator from a previous exercise in a model already, so I’ll use those.

Add the data in the Content Iso Symbol Definition through the properties palette.  Enter TYPE=MISC-COMPONENT, SKEY=PISC


While we use PI?? for our SKEY definition, the end type of the symbol should be screwed so, we are using PISC.  The MISC-COMPONENT category is one that gets placed in the bill of materials under fittings and doesn’t get extra information like end location added to it on the iso.

The produced isometric should look something like the following:


Here’s the symbol itself:


and the bill of material entry:



Creating a symbol not in the Bill of Material

The other question we got was, “How do I make a symbol that doesn’t show up in the bill of material?”

We will follow similar steps, but we are going to have to create the block in a different orientation due to using a different category.

Create a block called InstrumentDial. Because we are going to use the FLOOR-SYMBOL group, the insertion point has to be at the origin with the bubble off to the right.  My line is 1 1/8” long and the cirlce has a diameter of 1 1/8”.  Again, in the future, the program will probably be readying the dynamic point parameters, so I’m showing those.


To add your symbol key to the IsoSkeyAcadBlockMap.xml enter SKEY=ID?? for the symbol key and the block name, InstrumentDial.


In the model set the Content Iso Symbol Definition to TYPE=FLOOR-SYMBOL, SKEY=IDSC.



Here’s an iso showing both items:



Per our setup, the left is in the bill of material and the right indicator is not.


Thanks for checking out our article, feel free to leave feedback or contact us if you have questions.

Series NavigationSymbol for the Isometric Generator in AutoCAD Plant 3DCustom Parts Workflow

    followd this, it comes out not isometric, any ideas?

    • Maybe you haven’t put the symbol key information in the component in the model?