CTB vs STB Plot Style in AutoCAD: Key Differences and Usage

In AutoCAD, CTB (Color-dependent Plot Style) assigns plot properties like color and line weight based on object colors, while STB (Named Plot Style) assigns these properties based on named styles independent of color. CTB is simpler for color-based control, and STB offers more flexibility by separating plot styles from object colors.

Quick Comparison

Here is a quick side-by-side comparison of CTB and STB plot styles in AutoCAD.

Feature	CTB (Color-dependent Plot Style)	STB (Named Plot Style)
Control Basis	Based on object color	Based on named styles independent of color
Flexibility	Less flexible, tied to colors	More flexible, styles can be assigned to any object
Usage Complexity	Simpler to use	Requires managing named styles
Line Weight Control	Set per color	Set per named style
Color Control	Plot color depends on object color	Plot color set by style, can override object color
Common Use Case	Standardized color-based plotting	Complex projects needing style reuse

Key Differences

CTB plot styles assign plot properties like line weight, screening, and color based solely on the color of the object in the drawing. For example, all objects drawn in red will plot with the same line weight and color settings defined for red in the CTB file. This makes CTB easy to use when your drawing colors directly represent plot styles.

In contrast, STB plot styles use named styles that are assigned to objects regardless of their color. This means you can have multiple objects of the same color but with different plot styles by assigning different named styles. STB allows more precise control and flexibility, especially in complex drawings where color does not indicate plot properties.

Another important difference is that CTB ties plot settings to colors, so changing an object's color changes its plot style. STB decouples color from plot style, so you can keep object colors for visual clarity while controlling plot output separately.

CTB Plot Style Example

This example shows how a CTB file controls line weight based on color.

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Color: Red
Line Weight: 0.5 mm
Plot Color: Black

Color: Blue
Line Weight: 0.25 mm
Plot Color: Blue

Output

Objects drawn in red plot with 0.5 mm black lines.
Objects drawn in blue plot with 0.25 mm blue lines.

STB Plot Style Equivalent

This example shows named plot styles assigned to objects independent of their color.

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Named Style: ThickLine
Line Weight: 0.7 mm
Plot Color: Black

Named Style: ThinLine
Line Weight: 0.2 mm
Plot Color: Red

Object 1: Color Blue, Style ThickLine
Object 2: Color Blue, Style ThinLine

Output

Object 1 plots with 0.7 mm black lines despite being blue.
Object 2 plots with 0.2 mm red lines despite being blue.

When to Use Which

Choose CTB plot styles when your drawing colors directly represent how you want objects to plot, and you want a simple, color-based control system. This is common in standardized workflows where colors have fixed meanings.

Choose STB plot styles when you need more flexibility, such as assigning different plot properties to objects of the same color or when you want to keep object colors for screen display but control plot output separately. STB is better for complex projects with varied plotting needs.

Key Takeaways

CTB plot styles control plotting based on object color, making them simple and color-driven.

STB plot styles use named styles independent of color, offering more flexibility and control.

Use CTB for straightforward color-to-plot mappings and STB for complex or varied plotting requirements.

STB allows different plot properties for objects of the same color, unlike CTB.

Choosing the right plot style depends on your project's complexity and color usage.