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Diamond Version 5 User Manual: Polyhedra

Polyhedron Design and Hatching

In this article:
Design and Material Properties
Hatching
Displaying Polyhedra With Front Faces Open
Global Settings For All Polyhedra

Previous article: Creating polygons
Next article: Polyhedron selection and properties


Design and Material Properties

The design of a polyhedron face is made up of the following settings:

Style

Defines if the faces are open, partially open or closed.

Interior color

Defines the color that is used to fill the interior of the polyhedron faces.

Interior brush

Offers several options for the interior, like hatching, transparency, etc.

Edge color

Defines the color that is used to draw the edge of the polyhedron face.

Edge pen

Offers several options for the edge, like a dotted edge or no edge.

Edge thickness

Defines the line thickness for the edge or zero if no edge shall be drawn.

Specular and emissive reflectivity, shininess

Defines the behaviour of the polyhedron faces in rendered representation.

Transparency

Offers transparent faces in rendered representation.

Hatching

Offers real 3D hatching. For details, see "Hatching".

Since rendered representation uses neither edges nor patterns or hatching, some of the above settings will be used only in flat representation.

To define the design for new polyhedra, push the Polyhedron Design... button in the Add Polyhedra dialog or the Design... button in the Construct Polyhedron dialog. Furthermore you can change the designs of existing polyhedra.

Polyhedron Design dialog with Style and Colors page

The Style and Colors page of the Polyhedron Design dialog

The design of a polyhedron is described in the following:

Style

The polyhedron style determines if the polyhedron faces are all closed, all open or partially open. The style is defined in the Style combobox.

Open faces

All faces will be displayed open.

Front open

Back faces will be drawn closed, front faces open or closed. A face will be drawn transparent (open), if its normal vector encloses an angle less than the angle defined in Opening angle with the z-axis of the view coordinate system.

Closed faces

All faces will be displayed closed.

Interior of the polyhedron faces

Like for atoms or thick bonds, you can define a color and a brush for the interior of the polyhedron faces. Furthermore you can assign the central atom's main color, if you check the Use central atom's main color as interior color checkbox (which makes the individual color not unavailable). The main color is derived from the central atom's design: The main color is the interior color of an atom If the atom is hollow or has black or white as interior color, Diamond takes the edge color instead. If you do not use the central atom's main color, you can select a color from the color select box Color. The brush can be selected from the Brush combo box:

Solid

The default setting. The interior is filled opaque with the interior color.

Transparent

The interior of the polyhedron face is not filled.

Background

The interior color is ignored, and the background color is used instead.

Hatching 1, 2,...

The interior is filled opaque with the interior color, and a hatching is used with the pattern color. Please note that standard MS Windows hatching brushes are used for this option, which depends on the resolution of the output device. That means the density of lines is much more higher on a 600 dpi printer than on the screen (about 100 dpi). It is not recommended to use this kind of hatching; you should make use of the 3D vector hatching instead.

Edge of the polyhedron faces

You may define an edge for the polyhedron faces or not. The thickness of the edge is defined in millimeters in the Thickness input field. The color is selected from the Color select box in the Edge group. The pen can be selected from the combo box Pen:

Solid

The default setting. The edge is drawn as solid line with the edge color and the given thickness in millimeters.

Dash

The edge is drawn as dashed line with the edge color, whereas the thickness is ignored.

Dot

The edge is drawn as dotted line with the edge color, whereas the thickness is ignored.

No edge

Draws no edge.

Background

Draws the edge solid, but ignores the edge color and uses the background color instead.

Material properties

The Material button opens the Materials Settings dialog and offers you several material properties for the rendered representation of polyhedron faces. In principle these settings behave like for atoms and thick bonds; compare the article "Material Properties". Material properties take no effect for flat representation.

 


Hatching

In flat representation mode, you can use real 3D hatching for the polyhedron faces. Unlike the pre-defined MS Windows hatched brushes, this kind of hatching is done by drawing 3D lines across the polyhedron faces. These hatching lines are oriented against a hatching vector to define the preferred orientation of the hatching lines to be parallel with the polygon edges.

Hatching is not used in rendered representation mode.

Hatching is defined on the Hatching page of the Polyhedron Design dialog.

Polyhedron Design dialog with Hatching page

Selecting hatching

The combo box Style defines if and what faces are to be hatched. You may choose one of the following settings:

No hatching

None of the faces will be hatched.

Front faces only

Front faces will be hatched but not back faces. This option is useful for either closed or front open polyhedra.

Back faces only

Back faces will be hatched but not front faces. This option is useful only for front open polyhedra, since only these enable a view to the back faces.

All faces

All faces will be hatched.

Orientation of hatching

For each polyhedron face (polygon), the hatching lines are parallel to one of the polygon's edges. When Diamond selects this edge, it uses that edge that is at most vertical with the "hatching vector". The three components of the hatching vector are defined in the input fields Vector, X... The three components of the vector refer to the reference coordinate system. The distance between the (parallel) hatching lines is given in Angstroems in the input field Distance. When you change the enlargement factor the distance increases and decreases with the corresponding amount.

Relative length for each hatching line

If this value in the input field Relative length... is 1 (default value), the hatching lines touch the polyhedron edges. With a value between 1 and 0 these lines will be drawn shorter. E.g. with a value of 0.8, 10 percent at each end of the line will be omitted. This option may be used to contrast with the polyhedron edges.

Style, color, and thickness of the hatching lines

The color of the hatching lines is defined by the color select boxref_colorbox Color, whereas the combo box Pen defines, if and how lines will be drawn. The input field Width defines the thickness of solid hatching lines in millimeters. Please note that "dashed" and "dotted" lines will use only one pixel of thickness, regardless what is defined in Width.

Polyhedra example 3

Two illustrations of a Si-O tetrahedron in alpha-quartz. Both with a hatching distance of 0.3 Angstroems. The left picture uses the default value for the "Relative length of each hatching line" of 1.0, the right one a value of 0.95, so that the hatching lines do not touch the polygon edges.

 


Displaying Polyhedra With Front Faces Open

Since you must select polyhedra via the associated central atom, you may get problems when you use of polyhedra with closed faces (the regular case). It may be difficult and tedious to match the invisible central atom for selecting.

To avoid this, Diamond offers a function that hides temporarily all front faces of all polyhedra. Please note that this does not change the polyhedron style from close faces to front faces open, and this property will not be saved with the Diamond Structure Document. When all front faces have been opened, you can easily access the polyhedra's central atoms.

To open polyhedron faces temporarily, push the Picture Settings button in the Picture toolbar and choose the Open Polyhedron Faces command:

Open Polyhedra Front Faces toolbar button

Or choose the Hide command from the Display menu, and check the Hide front faces of all polyhedra checkbox in the Hide dialog.

Polyhedra example 4

The Sodalite example with temporarily open polyhedron faces.

 


Global Settings For All Polyhedra

While most of the settings can be defined individually for each coordination polyhedron, some settings apply globally to all polyhedra. To change these settings, go to the Others page of the Polyhedron Design dialog.

Polyhedron Design dialog with Others page

These settings are:

Darken back faces

If this checkbox is checked, the back faces are drawn darker than front faces. This makes it easier to distinguish between front and back faces if polyhedra are particularly open.

Show internal bonds

If this checkbox is checked, bonds (as far as defined) between central atom and ligand atoms will be drawn. This setting is not useful for closed polyhedra.

Ligand atoms reducing factor

Defines a factor between 0.0 and 1.0 that reduces the radii of all atoms which are ligand atoms of any polyhedra. That means a value of 1 does not have any influence to the atoms' original sizes, whereas a value of 0 suppresses these atoms completely.

Polyhedra example 5

The structure of alpha-quartz, both using Si-O tetrahedra. The left picture uses a ligand atoms reducing factor of 0.3, the right one a factor of zero, which means that no ligand atoms are drawn.

 


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Next article: Polyhedron selection and properties