Creating a piping isometric drawing

Creating piping isometric drawings in CAD is essential for mechanical and piping systems. This tutorial will explore two methods: plain AutoCAD and the Mech-Q add-on or AViCAD for enhanced functionality. By the end of this tutorial, you’ll be equipped to create ISO pipe drawings and efficiently generate a Bill of Materials (BOM).

In addition to using specialized software like AViCAD, we’ll explore the traditional method of creating ISO drawings. This will provide a comprehensive understanding of the process and discuss both manual and automatic methods for creating isometric piping drawings.

Method 1: Creating an ISO pipe drawing Using F5 Shortcut (Plain AutoCAD method)

The simplest way to activate Isoplanes in vanilla AutoCAD is by using the F5 shortcut. Isoplane (also referred to as Isogrid) refers to the three isometric drawing planes (top, left, and right) used to create 2D isometric drawings that give the illusion of 3D depth.

This method allows you to toggle between different Isoplanes and draw at a 30 or 60-degree angles, which is essential for ISO pipe drawings. You can also access drawing settings to adjust the Isoplane settings if needed.

YouTube player

For a detailed walkthrough of how to work in ISO mode watch video abive:

Step-by-Step Process:

Open AutoCAD:
— Start a new drawing or open an existing one where you want to create an ISO pipe drawing.
Activate ISO mode
— Type command SNAPSTYLE.
— Set this to 1 and Enter.
Alternatively, check Drawing Settings:
— If needed, you can further configure the Isoplane settings by accessing the Drawing Settings dialog:
— Type DS in the command line and press Enter.
— Navigate to the Snap and Grid tab in the Drawing Settings window.
— Here, you can fine-tune the isometric snap settings by adjusting the grid and snap options for each Isoplane.
— Apply the settings to match your project requirements, and click OK.
Toggle Isoplanes with F5:
— Press the F5 key on your keyboard to toggle between Top, Left, and Right Isoplanes:
– Top Isoplane: Aligns with the X-Y axis.
– Left Isoplane: Aligns with the Y-Z axis.
– Right Isoplane: Aligns with the X-Z axis.
Draw at 30 Degrees:
— Select the Line command (L).
— Specify a starting point, then set the angle to 30 degrees relative to the selected isoplane by typing 30 after specifying the start point and direction.

Example of how to draw a pipe valve in ISO view

Drawing in ISO provides a structured way to visualize and construct piping and mechanical components in a clear, dimensional format. This guide will cover key aspects of setting up your ISO drawing environment, using isometric views, and saving custom fittings for future use.

Start by selecting an ISO layout for consistent scaling, then use DIMSCALE in Mech-Q to ensure fitting sizes are proportionate. Tools like ISOVIEW, ISOPLANE, and the F5 key help you navigate isometric planes, making it easier to construct accurate angles and connections. Finally, tool palettes offer a streamlined way to save and reuse symbols, like a custom-drawn pressure release valve (PRV), across multiple projects.

Check out this ISO video for a hands-on example of creating an isometric PRV valve and saving it to your tool palette.

Method 2: Create ISO Drawings With The Mech-Q Tools

Mech-Q (an AutoCAD add-on) or AViCAD (a standalone CAD software) offers advanced features for ISO pipe drawings for a more streamlined process. These tools provide easier grid alignment, automatic fitting insertion, and BOM generation, making them ideal for more complex mechanical and piping systems.

Here is an overview of the steps we need to take when creating ISO pipe drawings:

Step 1: Setting Up the Isometric Drawing

When setting up the ISO drawing in AutoCAD, activate DIMSCALE in the configuration ribbon. Set the units as needed. The DIMSCALE factor should be set to 24 for working with half an inch. This number determines the size of annotations and dimensions in your ISO drawing.

Tip: To calculate your drawing limits, activate a viewport, zoom as required or use the anno scale list, then draw a rectangle to reach the extents of the viewport, and finally close the viewport. Switch to model space and you can see your drawing area or limits.

Launch Mech-Q or AViCAD:
— Open AutoCAD and load the Mech-Q add-on, or launch AViCAD directly if using it as a standalone software.
Start a New Drawing:
— Open a new drawing in Model Space and set the units to either English or Metric, depending on your project requirements.
— Define the drawing scale and sheet size.
— Create a title block as required.
Configure DIMSCALE:
— In the Mech-Q ISO Utility, set the DIMSCALE to match your desired scale. For example, if working in half-inch scale, set it to 24 to ensure proper scaling for annotations and dimensions.
— Maintaining Consistent Scale: With the help of the setting, DIMSCALE, Mech-Q keeps the size of our firrings consistent throughout the drawing. This includes sizes of fittings, valves, and welds – to ensure they are proportional to each other.
Activate the Isometric Grid:
— In the Mech-Q ISO dialog or AViCAD, choose the appropriate isometric grid that aligns with the 30-degree and 60-degree axes.
— This grid allows us to draw and align the piping components in a 3D-like isometric perspective.
Set Node Visibility and BOM Options:
— Adjust the node settings (e.g., set the size to 0.03 for visibility).
— Enable BOM options to itemize each pipe for easy tracking.

Step 2: Drawing the Piping Components

So, when working with Mech-Q for piping design, it’s important to remember the step-by-step process for defining the pipe route and entering pipe lengths. This involves activating the left ISO grid, entering a series of points to define the pipe route, and then inputting the pipe lengths at specific points.

We’ll be using direct distance input, which means specifying the precise distance between two points in a straight line. This provides an accurate way to define lengths or positions without relying on referencing points or measuring distances.

Let’s walk through the process together.

Select Components:
— Draw the Piping Components: Select the appropriate pipes, fittings, valves, and other components in the Mech-Q dialog box.
— Choose common components like straight pipes, elbows, and tees to build your piping system.
Draw the Piping Route:
— Follow the isometric grid to plot the piping system by specifying points.
— As you change directions, Mech-Q will automatically insert the necessary fittings, like elbows, based on the direction change.
Input Pipe Lengths:
— After drawing a pipe section, Mech-Q will prompt you to input the pipe length (e.g., 2 feet).
— Continue specifying lengths as you add additional pipe sections.
— Enable snapping as you enter points. This helps maintain the accuracy and proper alignment of the pipes and fittings.
Switch Between Each Isoplane:
— Change the grid view from Left ISO to Top ISO as needed, allowing you to draw pipes in different orientations without manually recalculating angles.

Step 3: Creating a Bill of Materials (BOM) and Annotations

In this step, we’ll add leaders and bubbles to pipe drawings using Ortho or Polar snapping. We’ll also discuss how to skip a bubble if needed and insert a BOM table or schedule of fittings. Additionally, we’ll explore scaling down the table using the SCALE command and moving it into the drawing sheet.

Open BOM Settings:
— In the ISO utility, navigate to the BOM settings and select your preferred table layout (e.g., a downward-building table).
Itemize Each Pipe:
— Enable the option to itemize each pipe for clear documentation of pipe lengths and materials.
Generate the BOM:
— Mech-Q will automatically create the BOM based on the drawn components, listing all pipes, fittings, and their respective lengths.
Insert BOM Bubbles:
— Label each pipe and fitting with leader arrows and place the BOM table within the drawing sheet.
Scale the BOM Table:
— If the BOM table is too large, use the SCALE command to resize it (e.g., 0.75 scale).
Adding Annotations:
— Mech-Q can also label the information about the piping system. This may include pipe sizes, lengths, and ratings.

Step 4: Plotting / Printing Your ISO Drawing

Once the ISO pipe drawing and BOM are complete, you can plot or print the final output.

Review your drawing to ensure it is easy to read and clear. Sometimes, you may have to scale the BOM schedule to fit on your drawing sheet.

This step lets you clean and organize your drawing during your Plot Previews.

Switch to Paperspace:
— Load Paperspace to prepare the drawing for plotting.
Set Plot Options:
— Open the Plot dialog by typing PLOT.
— Create a Plot Preview of your drawing.
— Choose Monochrome in the pen settings to produce a clean black-and-white print.
Choose Output Format:
— Plot the drawing to paper or save it as a PDF for easy sharing.

About Paperspace and viewports

Paper space might sound complicated, but it’s not as daunting as it seems. It’s simply a way to organize and present different views and scales of a drawing within the same file. Once you get the hang of it, you’ll find it’s a useful tool for effectively managing and presenting your designs.

Within a Paperspace layout, we can define the scale, create various views (called viewports), and add annotations, dimensions, title blocks, and borders. We can select the proper paper size by switching between different layout tabs.

Our template has three drawing sizes available, and we will be working on a 24 by 36 sheet.

Once the sheet is loaded, type MS for model space to activate the model space viewport. Alternatively, you can also double-click on the viewport.

We need to set the zoom scale in the model space. You can set this to 1/24, which is our scale factor, then type XP (1/24XP). You can also use the Annotative Scale list in the Status Bar and simply pull down the scale list there as well.

How to scale your ISO drawing within a viewport

To understand AutoCAD scaling, you need to familiarize yourself with a few key concepts:

DIMSCALE: As discussed above, DIMSCALE is a system variable in CAD that determines the scale factor used for dimensioning. It controls the size of dimensions, and even text, fittings, and even weld points in Mech-Q.

Viewports: Viewports are windows into your paper space drawing that allow you to see different parts of your drawing at various scales. You can create multiple viewports to display different areas of your ISO piping drawing at different scales. Each viewport can also have its own scale.

Zooming: Zooming allows you to adjust the magnification level of your drawing viewport. You can use the ZOOM command to zoom into a viewport or use the Annotative Scaling drop-down in the Status Bar for accuracy.

Understanding these concepts will help you work with scaling in CAD and ensure that your drawings are accurately drawn at the desired scale.

Comparison: Traditional AutoCAD vs. Mech-Q/AViCAD

Feature	Traditional AutoCAD	Mech-Q / AViCAD
Isoplane Activation	DS, F5 and Status Bar	Automatic ISO grid selection via dialog
Pipe and Fitting Insertion	Manual	Automatic insertion and pre-drawn fittings
Snapping and Alignment	Object Snaps	Automatic alignment along with Object Snaps
BOM Creation	Manual	Automatic BOM generation
Grid View Changes	Manual	Quick grid switching
Plotting/Printing	Standard	Titleblock and templates provided

Conclusion

For simple tasks, the F5 method in vanilla AutoCAD, combined with Drawing Settings (DS), offers a quick way to activate isoplanes and begin drawing at a 30-degree angle. However, for more complex mechanical or piping systems, Mech-Q or AViCAD provides advanced tools that automate much of the process, including BOM generation and automatic fitting insertion. Depending on the scale and complexity of your project, you can choose the method that best fits your needs.

Additional Resources

AutoCAD Isometric Forum: For additional support, visit the AutoCAD Forum.
Mech-Q Tools: Learn more about Mech-Q.
AViCAD Official Website: Explore AViCAD’s features at AViCAD.