3.9. Measurements

The tool allows you to make linear and polygonal linear measurements of distances in an image.

	The measurement accuracy is up to one screen pixel. As a screen pixel is smaller than a source image pixel, the true linear measurement accuracy is up to one source image pixel. Errors may also occur in density measurements. The most accurate measurements are performed with bilinear interpolation (see Section 2.4).

3.9.1 Ruler

To make linear measurements:

1. Activate the Ruler tool by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
2. Mark the first point on the toolbar by clicking the mouse button.
3. Drag the cursor over the screen. The distance from the first point to the current point will be displayed beside the line.
4. To fix the current point, click the mouse button.
5. To cancel an incomplete measurement, press Esc.

To move the ruler border:

1. Locate the cursor on the point to be moved.
2. Drag the point, holding the left mouse button.
3. Release the left mouse button.

To delete a ruler:

1. Locate the cursor on the line to be deleted.
2. Right-click the mouse and select the Delete all Measurement command.

This tool is also available from the model context menu and from the Volume main menu item. Activation is only possible with the left mouse button.

3.9.2 Polygonal Ruler

To perform plygonal linear measurement:

1. Activate the Polygonal ruler tool by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
2. Mark the first point on the toolbar by clicking the mouse button.
3. Drag the cursor over the screen. The distance from the first point to the current point will be displayed beside the line.
4. To fix the current point, click the mouse button.
5. Repeat Steps 3 and 4 until the last but one point is fixed.
6. Fix the last point by double-clicking the mouse.
7. To cancel an incomplete measurement, press Esc.

To move the linear measurement point:

1. Locate the cursor on the point to be moved.
2. Drag the point, holding the left mouse button.
3. Release the left mouse button.

To delete a point:

1. Locate the cursor on the point to be deleted.
2. Right-click the mouse and select the Remove point command.

To insert a point:

1. Locate the cursor on the ruler where you want to insert a point.
2. Right-click the mouse and select the Insert point command.

To resume a completed polygonal linear measurement:

1. Locate the cursor on the point from which you want to continue the measurement, so that it would look as follows: .
2. Right-click the mouse and select the Resume ruler command.
3. Perform the polygonal linear measurement.

This tool is also available from the model context menu and from the Volume main menu item. Activation is only possible with the left mouse button.

3.9.3 Corner 3D Meter

To measure an angle on the model:

1. Activate the Corner 3D meter tool by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
2. Make two points on the model clicking the mouse button. The second point is the angle apex.
3. Move the cursor over the screen to set the other side of the angle.
4. Click the mouse button to fix the second side of the angle.
5. To cancel an incomplete measurement, press Esc.

To move the corner 3D meter point:

1. Locate the cursor on the point to be moved.
2. Drag the point, holding the left mouse button.

To remove the corner 3D meter:

1. Locate the cursor on the line of the Corner 3D meter to be deleted.
2. Right-click the mouse and select the Remove corner tool command.

This tool is also available from the model context menu and from the Volume main menu item. Activation is only possible with the left mouse button.