Save Time with Symbol Assemblies in AutoCAD P&ID

David Ponka

If you are an AutoCAD P&ID drafter then chances are you have had to redraw common sets of P&ID symbols to represent a typical process, or arrangement of components, across multiple projects (let’s call these common sets of symbols assemblies for simplicity). You can speed your effort somewhat copying and pasting these assemblies from past project drawings but that can complicate documentation and tagging. I have a third option that you might find even more helpful. That is to group symbols together and add them to a custom tool palette so they can be placed as easily as any other individual P&ID symbol.


Take the valve assembly shown here. This set of symbols is a representation of one purchased component on a P&ID drawing. You can imagine that redrawing this on multiple drawings can get time consuming. Copying and pasting from other drawings, while significantly faster, still requires some extra effort. By taking these individual symbols, annotations & lines and making them a single block you can then take advantage of AutoCAD tool palettes to place the group of symbols all at once. The process isn’t necessarily straight forward though so let’s take a look at what’s involved.

Create a “Assemblies” Drawing file

Using AutoCAD P&ID, in a typical project, create a new project drawing and name it something like Assemblies.DWG. This is where you will draw the symbol assembly in the next step. Eventually this drawing will be removed from the current project and stored in a network location but we need to create this as a project drawing first to draw the initial layout of symbols and lines, etc.

Draw the Symbol Assembly

This might seem like a simple step but there are things to consider. You’ll need to ask yourself what symbols you want reported as separate line items in your line lists, valve lists and instrument lists, etc. In this example, all the graphics represent one purchased control valve assembly. So all the graphics, except the gate valve symbol at the bottom, are either annotations or a part of the control valve actuator symbol. The input air symbol and the electrical connection ID symbol (in black) are included in the assembly but they are separate classed symbols. The instrument balloons are drawn as annotations.

Create the Block

Now that all the symbols are placed and lines are drawn, use the standard AutoCAD BLOCK command (from within Plant 3D) to create a named block definition. Select all the objects and pick the insertion point that makes sense for placement of the assembly then give the block a descriptive name. Once the block has been created, save and close the drawing.


Remove the Assembly Drawing from the Project

Next you need to use the Remove Drawing command from the project manager to remove the drawing from the P&ID project. Then move the drawing from the project folder (project recycle bin folder in 2018) to a network folder so that anyone sharing the tool palette files with you will also be able to use the new assembly symbol. P&ID tool palettes work the same way as they do in AutoCAD so you will want to make sure that the drawing is centrally located as well as the tool palette configuration files.


Add to the Tool Palette

Once the drawing is moved to the network folder, still in AutoCAD Plant 3D/P&ID, use the AutoCAD OPEN command (NOT the Project Manager) to open the assembly drawing from its network location. With the assembly drawing open in Plant, as a non-project drawing, click and drag the symbol into the desired location on your tool palette. This symbol appears and is now a ‘Tool’ in the tool palette.


You’re almost set at this point but there’s one more critical part left. Since a block isn’t recognized as a P&ID symbol, even if it contains P&ID symbol(s), it has to be exploded when it’s placed in a P&ID drawing. The good news is that we can set the tool that we added to the palette to auto-explode each time it’s placed. Just right-click on the tool in the palette and select YES beside Explode. Now you can close the assembly drawing.


You're all set! Now when you are drawing AutoCAD P&ID drawings you can place the symbol assembly from the tool palette you’ve customized. The block will explode automatically leaving only the P&ID symbols, line & annotations from the original assembly. If you suffer from having to redraw common processes or copy and paste groups of symbols from one drawing to another this method can save you a significant amount of time.


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