OpenGL Hardware Acceleration for Pro/DESKTOP
Introduction
OpenGL is the proven industry standard for High Performance Graphics.
Pro/DESKTOP has been built to take advantage of hardware implementations of OpenGL.
With suitable OpenGL graphics hardware, you can enjoy the benefits of greater
responsiveness when working with large models and assemblies. With Pro/DESKTOP
2001, you can turn on some additional productivity enhancing features,
for example workplanes show as glass and smooth view animation. You will find these
in the Options dialog under the Tools menu.
In order to gain the performance benefits offered by an OpenGL accelerated graphics
board, you need to ensure that the configuration settings for the board match the
requirements made by Pro/DESKTOP. In most cases, if not all the requirements are met,
then Pro/DESKTOP will fall back to the software implementation of OpenGL and the
performance will be equivalent to not having an OpenGL graphics card installed.
Therefore, it is important to exercise care in choosing the display settings for the
graphics card.
The Pro/DESKTOP web site
provides a list of qualified OpenGL boards and driver versions which is updated
regularly. We encourage you to visit this resource for up-to-date information
regarding the status of graphics drivers.
If you have just bought a graphics card, you will have been given a driver, probably
on a floppy disk or CDROM. Graphics card manufacturers tend to update their
drivers frequently with continuing
improvements and usually provide a web site from which to download the latest
driver. We encourage you to update your graphics driver from the web. Since we can only qualify a limited
number of boards with a corresponding limited number of driver versions, you may well
be using a board or be running a driver version not on our qualified list. Use the
information on this page to help you determine what settings affect Pro/DESKTOP.
If you experience problems of a graphical nature in Pro/DESKTOP, or in the extreme case, if a
crash occurs when opening a new window, you can disable graphics hardware acceleration. Start
Pro/DESKTOP and open the Tools/Options... dialog. Under the General tab,
there is an option "Disable graphics hardware acceleration". Check the box to
disable acceleration.
How to determine whether Pro/DESKTOP graphics will be accelerated
In order to help you assess whether Pro/DESKTOP will be accelerated by your graphics
card in the current configuration, you can run GLtest,
a small, standalone test program that simulates part of Pro/DESKTOP 2001. When you run this program
it will tell you whether both Designs and Drawings will benefit from
acceleration via a pop up message. While the program is running, a console
window is displayed with more detailed information. You may wish to use the detailed
information when troubleshooting, or when experimenting with display settings that are
not mentioned on our list of qualified drivers.
Pro/DESKTOP Requirements
Pro/DESKTOP 2001 requires the following minimum requirements to enable acceleration:
- At least 15 color bits
- At least 16 depth bits
- At least 0 stencil bits for Design windows*, 4 bits for Drawing windows
- Double buffered main frame buffer
Graphics performance will be improved further by the existence of an overlay plane with at
least 2 color bits. In particular, an overlay plane improves pre-selection highlighting and
dynamics. Some cards support an overlay plane at lower resolutions, but due to a limited
memory resource, do not support one at higher resolutions. Pro/DESKTOP may run
with hardware accelerated graphics at the
higher resolution but there may be a trade-off with dynamics performance.
* If the graphics card does not support a stencil buffer, Design windows may
still be accelerated, but the View/Section... command will be disabled.
To enable the View/Section... command, it will be necessary to disable
graphics hardware acceleration from the Tools/Options... dialog.
Display Settings
We have provided below a brief glossary of terms that you might encounter when dealing
with a graphics card's display options and how they may affect Pro/DESKTOP. The generic display
settings - color depth, resolution and monitor refresh frequency - can be set from the Display
Control Panel applet which is best launched by selecting Properties on the right mouse button menu
over the desktop area. Refer to your graphics card manual for more specific options relating to the
hardware. You may find these presented as an additional tab in the Display Control Panel applet.
- Resolution
A generic screen setting. Although Pro/DESKTOP will run at any resolution, this setting
usually has a major impact on the other settings for an OpenGL card and can affect performance
significantly. Some OpenGL cards are optimized for a particular resolution or range of resolutions.
Most graphics cards contain a fixed amount of memory that is used for a number of different buffers
required for rendering scenes in OpenGL. Because of this, some cards may not be able to support
double buffering, overlay planes or stencil buffers at higher resolutions. Therefore, by raising
the resolution, you may inadvertently disable graphics acceleration. This setting should be
adjusted alongside other settings such as the color depth, refresh frequency and z-buffer depth.
- Refresh Frequency
A generic screen setting. This setting has no direct impact on Pro/DESKTOP, but depending on the monitor,
the speed of the graphics card DAC, and the chosen color depth, you may be restricted to lower refresh
frequencies at higher resolutions. Alternatively, you may want to upgrade your monitor if it cannot support
the refresh rate at your preferred resolution and color depth.
- Color Depth
A generic screen setting. Pro/DESKTOP requires at least 15 bits of color depth. This may be presented as
"High Color", 65536 colors or even 32768 colors. Setting the color depth to "True Color" (=24 bit depth)
will improve the shading quality of scenes, particularly Photo Album views. True Color may only be supported
if you have enough memory on the card or you are using a lower resolution. Some cards insist that
"True Color" be set in order to enable overlay planes. On some other cards, the color depth is stated as
32 bits, but this actually relates to a 24 bit main buffer and an 8 bit overlay plane.
- Depth Buffer (Z-buffer)
The depth buffer is used to hold depth information (the Z coordinate) for each pixel rendered to the scene.
This buffer is used to implement hidden line and hidden surface removal. Pro/DESKTOP requires a 16 bit depth
buffer for both Design and Drawing windows. However, when rendering certain very large, complex assemblies,
you may see small artifacts in the shaded image. These will be avoided by the use of a larger depth buffer
if your graphics card supports it.
- Double Buffering
Pro/DESKTOP requires a double buffered main frame buffer. Among other things, double buffering is responsible
for smooth display of changing scenes and fast repainting after highlighting. The way that the front and back
buffers are swapped is important to Pro/DESKTOP and varies according to the OpenGL implementation. Without an
overlay plane, buffer swapping is assumed to be done by copying the back buffer to the front buffer leaving the
back buffer intact. With an overlay plane, buffer swapping is assumed to be done by exchanging the buffers'
entire contents. If an option to control the buffer swap behavior is present, then you may need to adjust it
to rectify any problems you experience when not using an overlay plane.
- Overlay Plane
Overlay planes are supported by some OpenGL cards. An overlay plane is a seperate buffer that allows graphics to
be layered on top of the main buffer. If an overlay plane is present that supports at least 2 bits of color,
Pro/DESKTOP uses it to display pre-selection highlighted graphics and dynamic graphics during the creation and
modification of objects. From build 318 onwards, Pro/DESKTOP does not require an overlay plane in order to get
accelerated graphics, but an overlay plane will improve performance for pre-selection highlighting and dynamics.
If an overlay plane is not being used, the implementation of swapping the front and back buffers must be done by
copying. If an option to control the buffer swap behavior is present, then you may need to adjust it to rectify
any problems you experience when not using an overlay plane.
- Stencil Buffer
Pro/DESKTOP uses the stencil buffer to display clipped drawing views. Stencil buffers are not used in Design windows.
For Drawing views, a 4 bit stencil buffer is required. Without this, Drawing windows will not be accelerated, but
Design windows may still benefit from accelerated graphics.
- Texture or Bitmap Settings
Pro/DESKTOP does not currently perform any texture mapping and so all options related to this can either be turned off
or ignored. Some cards share their on-board memory between the frame buffers and texture buffers. Therefore, by turning
off texture settings, you may be able to free up resources for greater resolution or color depth.
- Pixel Format
This is not an option or a term that you will likely see presented in a user interface. It is an OpenGL term that is referred
to in the GLtest program supplied for diagnostics. When a Design or Drawing window is opened, Pro/DESKTOP selects a pixel
format that is best suited to the type of graphics that will be drawn to that window. This process selectively picks one
of the pixel formats that is offered by the OpenGL implementation. If none of the hardware pixel formats match the
requirements demanded by DesigWave, then the selection process will naturally fall back to select one of the pixel formats
with a Generic implementation (see below).
- Generic Driver
This is not an option or a term that you will likely see presented in a user interface. It refers to the software driver
that is provided by Microsoft to implement OpenGL upon the Windows graphical interface, called
GDI. The generic driver
requires no specific OpenGL hardware to run as its display driver is integrated with the GDI display driver.
An OpenGL board will typically provide its own driver that replaces the generic driver. This type of board has the potential
of accelerating all parts of the OpenGL pipeline. Some 3D graphics cards accelerate a smaller set of functions and their
drivers intercept calls under the generic driver. With such a graphics card, the GLtest program will indicate a GENERIC
implementation and report no acceleration even though rendering performance may be improved significantly.