Using GeoDome

When the user opens the GeoDome designer, this dialog appears:

The first group of controls on the left side of the dialog create the various forms of a geodesic sphere.

Frequency runs from 1 to 6, nd refers to the number of subdivisions on the faces of the selected geometrical solid. In general, higher frequencies create a requirement for more, shorter struts than a lower setting does; the faces are correspondingly more and smaller as well. Frequency 1 displays the basic solid.

The Basis is the solid chosen to be the beginning of the design. The choices are the Icosahedron, the Octahedron and the Tetrahedron.

The Class determines how the divisions in the faces at increasing frequencies are made. At higher frequencies the dome looks quite similar in either class, but there are differences in the length od struts and so on. FOr the moment, only Class 1 is allowed; CLass 2 will follow in an update soon.

The Truncation sets the amount of sphere that is sliced off the bottom in order to sit on the done's support. This can vary from 100% (no truncation at all) to 10% (only a thin "skull cap" remains). This should normally be set between 75% and 25% for realistic structures.

Below this first group of controls is the measurements section for the sphere, which scales the dome as required for the user's purpose. Note that the units of the measurements is defined by the main Punch! programs metric selection: if it is english, then inches to the tenth are displayed; if metric, to the millimeter. The units is displayed in the legend at the bottom of the left side of the dialog. The controls are:

• Sphere radius - the measurement from the center of the sphere to edge. It measures to the centerpoint of the wall at its maximal excursion away from the center - that is, at any face vertex.
• Sphere wall thickness - the thickness of the spherical shell.
• Sphere height - a read-only value, the height of the sphere taking into account the truncation.

A base may be added to a dome. The base will be a Punch! curved wall (which is actually a series of segmented straight walls). if the Base checkbox is selected, the base will be supplied, truncated radially just as the sphere may be, and the measurements made available for editing:

• Wall thickness - the thickness of the walls forming the base.
• Base height - the height of the base walls.
• Base segments - the number of base segments required to build the base.
• Segment length - a read-only display of the computed segment length of the walls making up the base. Make sure this value is high enough to accept the width of any door opening (including trim) you may want to build in the base.
• Base radius - the read-only display of the computed wall radius, based on the sphere radius and the height truncation.

On the right side of the dialog will appear a transparent wireframe representation of the sphere and base being defined. A pair of buttons at the bottom labelled Top View and Side viewcan be used to switch back and forth between a top-down view and a side view. The Rotation radio button allows the view to be adjusted to any desired viewpoint, continuously. Just turn on Rotation and then drag the mouse over the image.

The Help button invokes the Help documentation in a separate window. The Cancel button returns the user to PlansPlus without any work from GeoDome being passed on. The Export button sends the designed dome back to the Punch! plan, centered in the current view. It can be dragged to where it needs to be and rotated as desired at that point. The dome will be a single selectable 3D object, but the wall will be a typical collection of wall segments; make sure they are all selected before attempting to drag them anywhere.

GeoDome and the contents of this help file are
Copyright©2006 by ThistleKeep Engineering; all rights are reserved.
Comments and suggestions, as well as support, are entertained at Lmc@ThistleKeep.com.
"Punch!" and other titles of Punch! operations are trademarks of Punch! Software L.L.C.