User guide

Reducing ring size
You can reduce the number of atoms in a ring. For example, you can convert cyclohexane to cyclopentane. To reduce
the ring size, do one of the following:
Using the selection tool, click and drag.
Using a bond tool, point to an atom and SHIFT+drag. Release when one atom is on top of the other. The bond
between the atoms disappears.
Note: You can also move atoms using a selection tool. See "Moving objects" on page 42.
Bond crossing
When one bond crosses another, you can indicate which bond is in front. The bond which is behind the bond will have
a small section cutout, so you can clearly discern which is front-most.
1. Select the object to move to the front.
2. Go to Object>Bring to Front.
The selected object now appears in front of all other objects. Similarly, go to Object>Send to Back to position the
bond behind other objects.
Note: Some file formats store 3D coordinates for atoms, while others only store 2D coordinates. For bonds with
3D coordinates, those coordinates determine the visible bond crossings. Bring To Front and Send To Back have
no effect. For more details on converting bonds and structures into 3D view, see "3D viewing" on page 143
Fixed bonds
By default, ChemBioDraw draws structures with fixed bond lengths and bond angles. The values of those lengths and
angles is determined by the settings for the particular type of document. For more information, see "Document set-
tings" on page 273. However, you can modify the behavior so that you are not constrained to fixed bonds and angles.
Note: To suppress fixed lengths and fixed angles, press the ALT key as you drag the bond.
Drawing fixed length bond
To draw bonds constrained to a fixed length:
1. Go to Object>Fixed Lengths and ensure that a check mark appears next to the Fixed Lengths command.
2. Draw a bond using any bond tool.
Drawing fixed angle bonds
Bond angles are generally either set to the default chain angle of 120 degrees, or are constrained to angles of 15
degree increments. To draw fixed angle bonds:
1. Go to Object>Fixed Angles and ensure that a check mark appears next to the Fixed Angles command.
2. Draw a bond using any bond tool.
ChemBioDraw 13.0
Chapter 3: Basic drawings 15 of 401