Straight Lines and Arrows

CreatiCode

Prerequisite

Cylinders and Tubes

Introduction

Lines and arrows are commonly used in charts and illustrations. You can think of a 3D line as a thin tube that connects between 2 points.

The “Add Line” Block

The “add line” block has quite a few inputs. You can use this block to add a solid line, an arrow, or a dotted line.

Color Selection

You can set the initial diffusion color when you add a cylinder. You can update its diffusion/emission color, roughness or brightness later.

Diameter

The diameter controls how thick the line is.

Cap Type

The cap type controls whether the top and bottom faces of the line are covered up or open. For example, if the cap type is 'None", then you can see through the line like a tube.

Arrow Type

This input allows you to add arrowheads to the start or end point of the line, which converts the line into an arrow.

Sides

Since lines are just long and thin tubes, you can set their “Sides” similar to tubes. The more sides you specify, the more “rounded” the line looks. Since typically lines are very thin, a small “Sides” value like 4 to 6 should be good enough.

XYZ Position of the “From” and “To” Points

Since lines are used to connect between 2 points, you can specify the X/Y/Z positions of these 2 points directly.

This is a very convenient feature. Suppose we need to add a line between the point (0, 0, 0) and (100, 100, 100). If you have to use a tube, then you have to move and rotate the tube to connect these 2 points. However, with the “add line” block, you can specify these 2 points as inputs.

Segments: Segment Count for Dotted Lines

You can use this block to add dotted lines as well, using the “segments” input. If it is left blank, then you get a solid line. But if you specify a number, then the solid line is cut into this many segments. Each segment will be half solid and half empty.

The “Add Dotted Line” Block

When you add a dotted line using the “add line” block above, the segments and the gaps between them are of the same length.

If you need to make each segment longer or shorter relative to the gap between them, you can use the “add dotted line” block:

Here are 2 dotted lines with different segment lengths and gap lengths:

Demo

In this program, 12 white lines are used to form the frame of a box, and then 3 yellow dotted lines are drawn to connect 3 vertices into a triangle: