amira runs on Microsoft Windows 2000/XP, Linux (Red Hat Enterprise 3.0), Mac OS X Tiger (10.4), Sun Solaris 8 and 9, HP-UX 11.00, SGI Irix 6.5.x.

amira relies on fast hardware-accelerated OpenGL 3D graphics. We strongly recommend hardware texture mapping, since many visualization tools in amira rely on it. Hardware texture mapping is available, on all recent PC 3D graphics boards. On Unix systems it is available for example, on SGI O2, Octane and Onyx systems, on HP workstations with fx/4, fx/6 or fx/10 graphics, or on Sun Creator 3D, Elite, Expert 3D or newer graphics boards. For details on hardware acceleration, see below.

Apart from 3D graphics hardware probably, the most important system parameter is main memory. You should have at least 512 MB, preferably 2 GB or more. amira can also be started with less than 512 MB but it may decrease global performance.

The speed of the processor of course is also an important parameter. However it is less critical than the graphics system and the main memory size. For the PC versions, we recommend at least a 2 GHz processor.

11.5.1 On System Stability

amira is a very demanding application that extensively uses high-end features. Experience shows that such applications tend to reveal instabilities in system hardware, hardware drivers, and the operating system. A common problem is insufficient main memory. We recommend you configure enough swap memory in addition to physical memory. The total amount of virtual memory should be at least 1 GB. 2 GB would be even better.

Especially on PC platforms, OpenGL drivers today are often not as robust as desired. Also, system crashes due to bad memory chips or unstable power-supply are not rare. If you experience problems or instabilities with amira on your Windows platform, we recommend that you follow these steps:

1. Click on all the demo scripts in the Online User's Guide. If the system crashes, turn off hardware acceleration (choose the extended button from the Windows display settings dialog) and try again. If this eliminates the problem, there is a bug in your OpenGL driver. Try to get a new driver from the web site of the manufacturer of your graphics board.
2. Try using a different color depth in the Windows display settings dialog. Try 24 or 32 bit.
3. Load the lobus.am data set and visualize it with a Voltex module. Turn on the spin rotation (turn it with the mouse in the viewer and release the mouse button while moving the mouse, so that the object continues moving). Let it run overnight (turn off the screen saver). If the system has crashed or frozen the next morning, you probably have a hardware problem.

If this does not help, or if a reproducible error occurs on different computers, then it might be a bug in the amira software itself. Please report such bugs so that they can be eliminated in the next release or a patch can be prepared.

11.5.2 Microsoft Windows

amira runs on Intel or AMD-based systems with Microsoft Windows 2000 and Microsoft Windows XP.

Graphics Hardware: You should use a graphics board with OpenGL support and texture mapping capabilities. Both is the case for almost all newer 3D boards.

11.5.3 Silicon Graphics

Graphics Hardware: To get optimal graphics performance, the machine should support texture mapping in hardware. Currently this is the case for all O2 systems, and for Octane systems with High Impact, Maximum Impact (not Solid Impact) and Odyssey graphics. amira provides a number of modules which make use of texture mapping, e.g., slicing, pseudo-coloring, or volume rendering. On machines without hardware texture mapping, these modules either run much slower or may not work at all. The advantage of the Octane is a higher speed in polygon rendering. For a complex model with an isosurface of 100,000 triangles, the frame rate is 10 per second for an Octane, compared to 3 per second for an O2. The MXE and MXI Octanes have larger texture memory than the SSE and SSI. Thus the MXE and MXI enable a direct volume rendering using 3D textures, which is not possible on an SE, SI or O2.

Software: The current version of amira requires IRIX 6.5.x or higher. We recommend you install the newest version of the operating system (see http://www.sgi.com/support).

11.5.4 HP-UX

amira performs pretty well on HP workstations equipped with Visualize fx/4, fx/6+, and fx/10 graphics cards under HP-UX 11.00. Probably it will run on other machines as well provided the OpenGL runtime environment has been installed. In any case we recommend to install the texture acceleration option for your graphics system (hardware texture mapping), especially if you intend to work with large 3D image data sets.

Important: By default some HP workstations are configured with a data size limit of 64 MB for each process. In order to load reasonable data sets, you should increase this value to 1 GB and the stack size to 128 MB. Do this by modifying the values in sam/Kernel Configuration maxdsiz=0x80000000, ssiz=0x8000000, tssiz=0x8000000.