EVE-ElmerPost - a brief user's manual

This document gives a brief overview on how to use the EVE-ElmerPost (the EVE port of the CSC's ElmerPost software). It is assumed that the reader is already familiar with the workstation version, and thus only the things that differ from it are discussed.

Prerequisites

The EVE-ElmerPost runs in the SGI Onyx 2computer called "hermit.tml.hut.fi". Accounts for this computer are handled separately from the other accounts in the TML lab. If you don't have an account, please ask your contact person or administrator for assistance on this. You will also have to reserve the EVE beforehand (and have a permission to do so) in order to use the equipment.

1. Running EVE-ElmerPost

For making things easier, it is a good idea to cd to the ElmerPost application directory:

cd /p/projects/elmerpost/post/

The ready-made scripts, setting all the required environment variables for running EVE-ElmerPost are:

run_elmerpost : starts ElmerPost with the EVE configuration and using the tracker. This is the one you will probably use when working in the EVE.

run_elmerpost_notracker : starts ElmerPost with the EVE configuration without tracker. This can be used when the tracker is not available or you want to leave it free for someone else to use while working in the EVE.

run_elmerpost_dev : starts ElmerPost with a single window (not in the EVE) with tracker. For testing at a workstation.

run_elmerpost_dev_notracker : starts ElmerPost with a single window, without tracker. For testing at a workstation when tracker is not available.

If you get a message saying "command not found" or something similar, try typing "./" before the script name like this:

./run_elmerpost

If you are using the above scripts, and got ElmerPost running, you can skip to chapter 3.

2. Running EVE-ElmerPost manually

This chapter describes how to run ElmerPost without the ready-made scripts.

ElmerPost requires an environment variable ELMER_HOME to run. For example:

export ELMER_HOME=/p/projects/elmerpost

EVE-ElmerPost also uses FLUID library for tracking, which requires the following environment variables to be set:

export FLUID_ROOT=/p/projects/fluid/current
export LD32_LIBRARYN32_PATH=/p/projects/fluid/current/lib/IRIX-debug/:$LD_LIBRARY_PATH

Run EVE-ElmerPost with a script called "ElmerPost", found in the elmerpost/post/bin directory.

The parameters differ from the workstation version as follows:

-c filename : Specifies the MPK configuration file (required)
-headtrack : Use head tracking (do not use if the tracker is not available).

There are two configuration files available:

eve.mpconfig : EVE configuration, 3 walls, stereo, multisampling, runs in the EVE.
dev.mpconfig : Development configuration, one small window, runs on any workstation.

Head tracking option should only be used when tracker is on. Tracking must still be activated by pressing the "Tracking on/off" button in the main EVE-ElmerPost window (see "Tracker settings" below) The tracker values are read but ignored until tracking is activated within ElmerPost.

An example of running EVE-ElmerPost manually:

cd /p/projects/elmerpost/post
bin/ElmerPost -c eve.mpconfig -headtrack

3. Using the mouse

In the EVE-ElmerPost, the mouse is operated in a slightly different way that you may be used to. The right mouse button acts the same way as the shift key in the original ElmerPost (this is because of the way OpenGL Multipipe SDK handles events).

NOTE: When using the Logitech wireless mouse in the EVE, remember that the left button is physically moved to the right side. The other two buttons are ordered normally. For example, the LEFT+RIGHT button press described below can be accomplished by pressing the two rightmost buttons in the wireless mouse.

Moving the object:

LEFT button + mouse left/right moves object along the X axis
LEFT button + mouse up/down moves object along the Y axis
LEFT+RIGHT buttons + mouse up/down move object along the Z axis
LEFT+RIGHT buttons + mouse left/right move object along the X axis

Rotating the object:

MID button + mouse up/down rotates around X axis
MID button + mouse left/right rotates around Y axis
MID+RIGHT buttons + mouse up/down rotates around Z axis
MID+RIGHT buttons + mouse left/right rotates around Y axis

Scaling the object:

MID+LEFT buttons + mouse up scales object up (larger)
MID+LEFT buttons + mouse down scales object down (smaller)

Using the mouse in EVE-ElmerPost

4. Tracker settings and the main ElmerPost user interface

The main user interface window differs a little from the one found in the original ElmerPost. The button icons have been redesigned and the transformation arrows antialiased. The "Update all" button has been given a name and moved from the top right corner to make better use of the available screen space. A "Tracker on/off" button has been added.

The tracker settings are straightforward: Tracking can be set to on or off by clicking on the "Tracking on/off" -button in the main window.

You can also set the Motionstar's sensor used for head tracking by editing the "fluid-config" file in the "elmerpost/post" directory. The format is "sensorX = head", where X is the physical sensor number.

The ElmerPost main user interface window, tracking inactive

5. Camera Settings (Edit->Camera Settings, shortcut: S)

The amount of camera settings has been reduced somewhat in EVE-ElmerPost, compared to the desktop version, because all settings do not apply or cannot be used in an immersive environment.

From {x,y,z} settings affect the object position relative to the EVE in world space. Use this if you need to go further away from the object. The same effect can be achieved by moving the object using a mouse, but then the object is not in the world origin anymore.

Although the camera creation/loading functionality has not been removed from the menus, only one camera is supported in this version of ElmerPost. Don't bother to try and create or load camera settings with more than one camera, or the results will be undefined.

"Projection:" can either be perspective or orthogonal. Using an orthogonal projection in the EVE can be useful if you want to look at a model from several angles at a time. This resembles working with a setup with multiple cameras, although perspective projection is then not supported.

The Camera Settings window

"Clipping planes: Near" sets the near clipping plane. Like lower eye distance values, higher near plane values may also help when objects come too close for proper stereo effect (the image breaks up into two). The default value of 0.1 meters works in most situations. The far value works similarly to the workstation version.

"Eye separation" slider affects the interocular distance. The value equals half of the distance between the eyes in meters. Normally this is set to 0.035 meters, but may need adjustment in some situations: If the distance between the user and the object is very large, a larger eye distance value may be required for better stereo effect. Similarly, if the object is very close to the user, eye fatigue may occur with the default eye distance. In this case, try a bit smaller value.

6. Shortcuts

Several shortcuts have been added to the EVE-ElmerPost to ease the use of the user interface. The shortcuts work by moving the cursor to the graphics display area (so that it's not on top of any of the GUI windows) and pressing a key (either upper or lower case) from the keyboard. The shortcuts are:

esc - Quit ElmerPost
H - Open help window
C - Open camera settings dialog
F - Toggle displaying frames per second on/off (new feature, output goes to the current stderr)
S - Toggle stereo/mono viewing
O - Open file dialog
M - Open color mesh dialog
U - Open isocontours dialog
I - Open isosurfaces dialog
V - Open vectors dialog
P - Open particles dialog
G - Open group edit dialog
T - Open timestep edit dialog
Up arrow - Move forward
Down arrow - Move backward
Left arrow - Move left
Right arrow - Move right
R - Reset object transformations to default values

7. Things under construction

The following features of the original ElmerPost have not currently been implemented in EVE-ElmerPost:

Fonts (For example the colorscale displays no values because there is no font support yet).
Multiple cameras (they may be useful in some situations, but on the other hand they break the immersion in VR systems).
The up vector is ignored in camera settings.
Scriptable animation of particles (animation does work manually using the "Advance" button).
The "loop" button in the "Time Step Control" window does not work. However, the timesteps can be viewed (in real time) manually by moving the "Timestep control" slider (see below).

The timestep control window

8. Bugs

Changing the treshold values alone in the arrows dialog does not update the display. Some other value must be changed, or the "Update All" button used to see the effect.
When using "solid" line style for isocontours, the color variable has no effect (everything is displayed in one color).

This page is last updated 15.10.2002 by Seppo Äyräväinen