Installing Blobby Modeler
At the time of this writing, I have compiled Blobby Modeler
successfully on:
as well as library files for Tcl/Tk.
After compiling ET, place a copy of the files et.o and
et2c in the bm1.0 directory. Edit the
Makefile as necessary to point to the Tcl/Tk library files
and make the software.
Here are some additional files that might be useful:
- Help file with a few minor corrections that
didn't make it to the distribution package.
- Sample DX program to help you get your own
blobby model started.
Using Blobby Modeler
The following text is taken from the on-line help of the software, and
slightly reformatted for HTML.
Table of Contents:
- Getting started
- Drawing atoms
- Editing atoms
- Loading from and saving to disk
- Exporting to IBM DataExplorer
- Changing the options
- Accelerator keys
Getting started:
The main editing window of Blobby Modeler is subdivided into four
smaller two-dimensional windows. The upper left window is the xy
window, in which all atoms of the same x- and y-coordinates
but different z-coordinate will be displayed as overlapping. The
upper right window is the yz window, and the lower left being the
xz window. A small label is placed in the positive direction of each
axis. At the lower right is a special window called the free window.
It allows a user to view the object being edited from any angle or
orientation. The free window cannot be edited.
At the bottom of each window, you will find a row of buttons with corresponding
icons inside them. For the xy, yz, and xz windows,
clicking mouse button 1 (usually the leftmost) on the the buttons have the
following meanings:
- Pencil
- Enters the "drawing" mode (and leaves the "select" mode).
- Black Arrow
- Enters the "select" mode (and leaves the "drawing" mode).
- Hollow Arrows
- Moves the viewport in the direction shown, if possible.
- Magnifying Glass with a '-'
- Zooms out the viewport to see a larger portion of the field.
- Magnifying Glass with a '+'
- Zooms in the viewport to see more of a smaller portion of the field.
The "drawing" or "select" mode buttons apply to all three editing windows, so
clicking on any of them will have the same effect. Different magnification
levels and viewport positions are possible for each of the three editing
windows, and clicking on one of them will not affect settings on another window.
Clicking on the icons underneath the free window have the following meanings:
- Arrows
- Rotates the object in the window in the direction shown
- Magnifying Glass with a '-'
- Zooms out the viewport to see a larger portion of the field.
- Magnifying Glass with a '+'
- Zooms in the viewport to see more of a smaller portion of the field.
On top of the editing windows, you will find a row of menu items with the words
"File", "Edit", and "Options". Clicking on these will each present sub-menus
with various choices.
Drawing Atoms
To start drawing, click on any of the pencil icons. If you move your mouse
over any of the editing windows, you will find that your mouse cursor has
changed to cross-hairs (like "+"). This indicates that you are now in the
"drawing" mode.
Position the mouse cursor over a spot which you intend to be the
center of the atom, and click mouse button 1. A small dialog box
should pop-up which prompts you to enter the strength of the atom. Keep in
mind that the drawing volume is from -1 to 1 inclusive in all three axes, so a
strength more than 1.0 would probably not make much sense. Strengths can also
be negative, in which case will contribute negatively to the surface
generated. Negative strengths are never visible, but will be seen as dents if
they are close to an atom of positive strength.
By now, an atom should have appeared. Do not worry if it is not in the correct
position. Since a mouse is only a two-dimensional input device, Blobby
Modeler supplies the missing coordinate as 0.0. For instance, if you draw
in the "xy" window, the z-coordinate of anything you draw will be zero. You
must move the atom into its correct place using possibly one of the other
windows.
Editing Atoms
Click on the black solid arrow icon now. Wiggle your mouse cursor over one of
the editing windows to make sure that the cursor is now an arrow. It means
that you are now in the "select" mode.
In any of the editing windows, click on an atom. Be careful to click on the
edge of the atom, instead of the center. The atom you clicked on
should turn blue to indicate that it is currently selected. All the items in
the "Edit" menu are now applicable on the selected atom. You could now:
- Cut
- This action deletes the atom from the edit windows and places it in the
clipboard.
- Copy
- This action creates a copy of the atom in the clipboard, but does not
delete it.
- Paste
- This action copies the contents of the clipboard, if any, onto the drawing
windows.
- Select All
- Instead of clicking on each atom, this command allows you to mark all atoms
in the editing areas as currently selected.
- Strength
- This action allows you to adjust the strength of the currently selected
atom.
By simple holding down mouse button one over any atom and releasing it over a
new location, you can move the atom in any editing window. This is referred to
as "dragging" the atom. You may only drag one atom at a time.
File Operations
When you have completed your drawing, you will want to preserve a permanent
copy. This and others can be done by invoking the items under the "File" menu:
- New
- This action clears the editing windows and leaves you with a clean sheet to
work on. Because of its consequences, this action will seek confirmation.
- Open
- This action loads a previously saved Blobby Modeler file.
- Save
- This action saves a copy of the current drawings to a file.
- Save As
- This action is the same as "Save" but allows you to select another file
name.
- Quit
- This action exits Blobby Modeler and returns to the operating
system shell, after seeking confirmation.
To prevent costly errors, the software pops up windows confirming your action.
The "Open", "Save", and "Save As" items will present a dialog box requesting
for a file name, listing all appropriate files (*.bm) in the
current directory. You may double-click mouse button one on any of the choices
presented to select them.
In the case of permission problems (trying to write to a read-only file, etc),
the software will warn appropriately, and abort the action selected. It will
not make an attempt to override the settings in the directory entry.
Exporting to IBM DataExplorer
When you are satisfied with your design, it will be time to transfer the data
over to IBM DataExplorer for final rendering. For this
action, select "Export" under the "File" menu, and you will see a new dialog
box.
The topmost item in the dialog box is the file name you wish to save the file
to. By default, IBM DataExplorer expects a file with the extension
".dx". Some other important options are available as well. In order to
prevent the additional overhead of scaling or translating in IBM
DataExplorer, Blobby Modeler provides options to change the origin of the
field, as well as the scale of the field. Likewise, six possible resolutions
are presented for your choice, from 21 x 21 x 21 up to 71 x 71 x 71. The
higher the resolution, the longer it will take both Blobby Modeler and IBM
DataExplorer to generate the results.
When you are satisfied with the options, click on "Proceed". The software will
idle for a while, depending largely on the complexity of the scene, the chosen
resolution, and of course the processing speed of the computer. When it is
done, you will simply be returned to the editing screen. The file is now ready
to import into IBM DataExplorer.
In the simplest case, IBM DataExplorer will require only three modules
to display the result of Blobby Modeler's work. You start with an
Import module, specifying the file name.
The read input should enter an Isosurface module, which is responsible
for the actual generation of the surface. It requires a threshold value
parameter, which should generally be 0.5, but any other value is just as
valid. Increasing the threshold will "shrink" the object and decreasing it
will "enlarge" the object.
The rest is simple. Just run the object through an Image module, and
the blobby model is complete.
The user must be careful, however, about selecting very high sampling
resolutions. A 71 x 71 x 71 field will generate over 350,900 data points! A
good idea would be to start with a relatively low resolution (the default 31 x
31 x 31 is a good choice) and increase resolution only when necessary.
Changing Options
Blobby Modeler provides three options that a user may select from under the
"Options" menu. The first option, "Free Window", turns the updating of the
three dimensional view on or off. Turning off the display may be advantageous
at times especially if the computer is not very fast. The second option,
"Grid", turns the screen ruler grids on or off. The grids are usually useful
as they provide a cue to where in the field a node is. The last item is "Grid
size", which can be used to select a custom graduation for the grids. This is
useful if you wish to place a node rather accurately at a position, or if you
work in a high-zoom window where the default grids will be too far apart.
Accelerator Keys
Blobby Modeler provides full functionality through its menus and
buttons, but also provides keyboard shortcuts for the more experienced user.
The keys are listed below: (Ctrl-a, for instance, denotes that
the Ctrl modifier key be held down while the a key be
pressed)
- Ctrl-a Select all
- Ctrl-c Copy
- Ctrl-e Export
- Ctrl-n New file
- Ctrl-o Open file
- Ctrl-q Quit program
- Ctrl-s Save file
- Ctrl-t Set strength
- Ctrl-v Paste
- Ctrl-x Cut
Last Modified: May 18, 1995
Szu-Wen (Steven) Huang