Hidden Lines On A Stock Drawing Should Be Made Using: Complete Guide

Ever stared at a CAD sheet and wondered why some lines are simply invisible?
It’s the hidden lines—those faint, dashed strokes that hint at shapes you can’t see from the chosen view. They’re a staple in engineering drawings, architectural plans, and industrial sketches. If you’ve ever tried to recreate a stock drawing and felt lost, you’re not alone. The trick is simple: hidden lines should be made using a consistent, recognizable style—usually a dashed line. But there’s more to it than just “dashes.” Let’s dig in.

What Is a Hidden Line?

Hidden lines are the imaginary outlines of parts that lie behind other geometry from the current viewpoint. They’re not visible in the real world from that angle, but they’re crucial for understanding the complete shape. Think of a pipe running inside a wall: from the outside you can’t see it, but a hidden line tells you it’s there Not complicated — just consistent..

Quick note before moving on.

In practice, hidden lines give depth to a flat sheet, letting the reader infer 3‑D structure without additional views. They’re a visual shorthand—no need for a full exploded view or multiple orthographic drawings And that's really what it comes down to..

Types of Hidden Lines

• Standard hidden lines: Dashed or dotted lines that represent fully hidden edges.
• Break lines: Short dashes indicating a break in the edge, often used for long hidden segments.
• Hidden line removal (HLR): When a surface is completely hidden, the line may be omitted entirely, relying on shading or other cues.

Why It Matters / Why People Care

You might ask, “Why bother with hidden lines at all?” Because they save space, reduce clutter, and preserve the integrity of the object’s geometry The details matter here..

• Clarity: Hidden lines prevent the reader from guessing where a surface ends. Without them, the drawing can look ambiguous.
• Compliance: Many standards (ISO, ANSI, DIN) require hidden lines to be shown in a specific way. Failing to do so can lead to misinterpretation or even legal issues.
• Efficiency: A single sheet with hidden lines can replace multiple views, cutting drafting time and printing costs.

When hidden lines are missing or inconsistent, you risk miscommunication. Now, an engineer might misread a part’s thickness, or a fabricator might cut the wrong shape. That’s why the industry has settled on a convention: dashed lines.

How It Works (or How to Do It)

The Basic Rule: Dashed Lines

• Line style: Typically a series of short dashes separated by short gaps.
• Line weight: Often the same weight as visible lines, unless a lighter weight is required for emphasis.
• Color: Usually black or gray, matching the rest of the drawing.

Setting Up Hidden Lines in Popular Software

AutoCAD

1. Open the drawing and go to View > Drafting Tools > Line Style Manager.
2. Create a new line style named “Hidden.”
3. Set the line type to Hidden (the built‑in dashed style).
4. Apply the style to any edge you want to hide: select the edge → right‑click → Properties → Line Type → Hidden.

SolidWorks

1. In the Sketch or Model view, right‑click the edge → Properties.
2. Under Line Settings, choose Hidden.
3. SolidWorks automatically toggles the edge to a dashed line.

SketchUp

1. Select the edge.
2. In the Entity Info panel, change the Line Type to Hidden.
3. The edge turns dashed instantly.

Fusion 360

1. Right‑click the edge → Edge Properties.
2. Set Line Type to Hidden.
3. The line updates to a dashed pattern.

Customizing Hidden Lines

Sometimes the default dash length is too long or too short. Most tools let you tweak it:

• AutoCAD: Edit the line type definition file (.lin) to adjust dash and gap lengths.
• SolidWorks: Use the Line Type dialog to set custom dash patterns.
• SketchUp: Install a plugin like “Hidden Line” to modify dash spacing.

Visibility Settings

Hidden lines can be turned on or off globally:

• AutoCAD: HIDDEN layer visibility toggle.
• SolidWorks: Display > Hidden Lines checkbox.
• SketchUp: View > Hidden Line option.

This is handy when you need a clean, flat view for printing or when you’re focusing on a specific part of the assembly.

Common Mistakes / What Most People Get Wrong

1. Using the wrong line style
   Some draftspeople accidentally use a dotted line or a short dash that looks like a break line. The result is confusing.

2. Inconsistent dash lengths
   Mixing short and long dashes in the same drawing breaks the visual rhythm and can be mistaken for a different line type Nothing fancy..

3. Applying hidden lines to visible edges
   A hidden line on an edge that’s actually visible from the view is a red flag—readers will think there’s a mistake in the drawing.

4. Overloading a sheet
   Adding hidden lines to every single edge can clutter the sheet. Use them sparingly: only where a surface is truly hidden It's one of those things that adds up..

5. Ignoring standards
   Every industry has its own line weight and dash length guidelines. Skipping those can lead to non‑compliance.

Practical Tips / What Actually Works

• Keep it consistent
  Pick one dash pattern per project and stick to it. If you’re working in a team, share a line style template Easy to understand, harder to ignore..

• Use layers wisely
  Put hidden lines on a dedicated layer (e.g., “Hidden”) so you can toggle them without touching other geometry.

• put to work shortcuts
  AutoCAD’s HIDDEN command or SolidWorks’ H hotkey instantly switches between hidden and visible lines.

• Test print
  Hidden lines can look different on screen versus paper. Print a test sheet to ensure the dashes appear crisp.

• Document your choices
  In the drawing’s title block or a notes section, state the dash length and line weight. This helps anyone reviewing the drawing later.

• Use color sparingly
  While most standards call for black, some firms use a lighter gray for hidden lines to reduce visual noise. Just make sure it’s approved.

• Automate with scripts
  If you do a lot of drawings, write a small script (AutoLISP for AutoCAD, a macro for SolidWorks) to apply hidden line styles automatically And that's really what it comes down to..

FAQ

Q1: Can I use a different line weight for hidden lines?
A1: Standards usually recommend the same weight as visible lines. If you need a lighter weight for emphasis, document it and get approval.

Q2: What if the part has multiple hidden surfaces?
A2: Apply hidden lines to each edge that’s fully obscured. If an edge is partially hidden, use a break line instead.

Q3: Is it okay to omit hidden lines altogether?
A3: In some simplified sketches, you might. But for formal engineering drawings, hidden lines are essential for clarity and compliance Still holds up..

Q4: How do I handle hidden lines in a 3‑D rendering?
A4: Render the model with a “wireframe” or “hidden line” view mode. Most rendering engines have a preset for this.

Q5: Can I use a custom dash pattern for my company’s brand?
A5: Only if it doesn’t conflict with industry standards. Keep the pattern recognizable and avoid anything that could be mistaken for a break line.

Closing

Hidden lines are the unsung heroes of technical drawings. By following a simple rule—using consistent dashed lines—and paying attention to detail, you turn a plain diagram into a clear, professional communication tool. They bridge the gap between a flat sheet and the three‑dimensional world it represents. Next time you draft a stock drawing, remember: a well‑placed dash can save hours of rework and keep everyone on the same page.