Measure properties involving the
Angle between atoms and other objects.
Property
The supported
Angle properties, the same as for
Atom->Modify, are listed below. Atoms and other objects
may belong to different parents and may be bonded or not.
Only objects in the current layer can be chosen.
An easy technique to select the objects is to click the mouse
sucessively over their visual representations, in the sequence
shown in the dialog. After the last needed object is selected,
GAMGI automatically starts the calculation.
3-Atom Angle
The valence angle between directions Atom2-Atom1 and Atom2-Atom3.
The signal convention is: when vector Atom2-Atom1 is rotated from
vector Atom2-Atom3 through a direct, counter-clockwise rotation,
the angle is positive, otherwise is negative. In 3D space, the direction
of this planar rotation depends of the side of the plane where the user
is, so the angle signal depends of the user position relatively to the atoms.
4-Atom Angle
The torsion angle between two planes, defined by Atom1-Atom2-Atom3
and Atom2-Atom3-Atom4. An error is shown when Atom1, Atom2, Atom3 or
Atom2, Atom3, Atom4 are initially aligned along a common direction,
because the plane Atom1-Atom2-Atom3 or Atom2-Atom3-Atom4 is undefined.
The signal convention is: looking along vector Atom2-Atom3
(with Atom1 near the user and Atom4 away from the user), when vector common
direction-Atom1 is rotated from vector common direction-Atom4 by a direct,
counter-clockwise rotation, the angle is positive, otherwise is negative.
While the signal of the 3-atom angle depends of the user position, the
signal of the 4-atom angle is unique, because the four atoms define a 3D
construction while the three atoms define only a 2D construction. If the
user is looking from the other side, along the common direction Atom3-Atom2
(with Atom4 near the user and Atom1 away from the user), the user now sees
the rotation in the opposite direction, which compensates the Atom1, Atom4
swap, so the signal of the torsion angle remains the same.
Value
After selecting a property, enter the name of the objects and
press
Ok. If all objects are recognized, GAMGI does the
calculation and shows the result in the
Value entry.
When a calculation ends, GAMGI keeps the objects identification.
To start a new calculation, just click the mouse over a new object:
GAMGI automatically cleans the previous data and inserts the new
object identification. When a new property or page is chosen,
previous data is automatically removed.