QV 4

QV window



A Windows Layout render display, requires LightWave 6.0 or later.

Introduction | How It Works | Toolbar | Config File | Memory Usage | Updates


QV is a lightweight, fast alternative to the image viewers that ship with LightWave. The first version was a free plug-in released in the summer of 1996, shortly after LightWave 5.0. The following spring, the second version was bundled with LightWave, and about a year and a half after that, I released the third version as a modestly priced commercial product. QV 4, released in 2005, takes advantage of some improvements to LightWave's plug-in programming interface introduced in LightWave 6.0.

If you've used previous versions of QV, the most important changes in QV 4 are floating-point pixels and improved image saver access. This version supports drag-scrolling, and it remembers the render time and some other scene settings for each image. It also addresses, although it doesn't entirely solve, a problem created by changes in Microsoft Windows that affect the ability of plug-ins like QV to bring their windows to the foreground.

People tend to assume that QV is short for Quick Viewer or somesuch, which is fine, but it's actually a nod to coworker friends from my salad days, when I worked in an insurance company clerical department called Quality Verification.

How QV Works

Install QV as you would any other plug-in, after which you'll find it in the Render Display list on the Render Options panel. At the end of an F9 render in LightWave, QV opens a window to display your rendered image. QV stores two versions of the image. One is the original floating-point image as it was received from LightWave. The other is a 32-bit version created for QV's display.

QV automatically dismisses LightWave's Render Status dialog box. The information shown there (the render time and a settings summary) is duplicated in QV and can be found on the Notes tab of the Notes and Settings dialog (keyboard shortcut n).

QV can hold up to ten images at a time. If all ten image slots are full, the next image to arrive replaces the oldest image. If you close QV's window (using the Esc key or the close box in the window's title bar), QV discards all of its stored images. If you minimize the window, QV retains all of its images. QV minimizes onto the Windows taskbar to keep it out of the way of Layout's interface and to make it easy to find later. When a new image is rendered, QV automatically reopens its window, or restores it if it's been minimized. You can switch between images using the radio buttons along the bottom of the window, or by hitting a number key (the first image is 1 and the tenth is 0).

Mouse clicks change the image zoom. The left mouse button zooms in, centering the image on the pixel you click on. The right button zooms out. You can also zoom from the keyboard using the comma ( , ) and period ( . ) keys, which on U.S. keyboards are the unshifted left and right angle brackets ( < and > ). These are the same as the default keys in Layout for zooming the view. The current zoom level is displayed in the status bar at the bottom of the QV window.

If the image is larger than the QV window, you can pan or scroll it. Scrollbars will appear on the right and bottom edges of the image. You can also drag the image with the mouse by holding down the Ctrl key and the left mouse button and moving the mouse. On the keyboard, the cursor keys move the image four pixels at a time (or 64 if you hold down the Shift key). Home and End move to the left and right edge, and Page Up and Page Down move to the top and bottom edge.

The status bar displays the name of the image, the zoom level, the pixel coordinates at the mouse cursor's current position, and the color of that pixel. The pixel color can be displayed as byte (0 to 255) or floating-point (0.0 to 1.0) values. You set this option on the Levels tab of the Notes and Settings dialog. The image name can be changed on the Notes tab. This is also used as the default filename.


The toolbar along the top of the QV window gives you access to most of QV's functions and settings. Each of these also has a keyboard shortcut.

Save   s
Save the current image. You can use any of LightWave's plug-in image savers or QV's built-in Windows BMP and Amiga IFF savers. If the alpha channel is currently displayed, QV saves just the alpha, as a grayscale image. Otherwise it saves the full-color image, including the alpha if the file format supports it.

QV sends the original floating-point pixels to the image saver, just as they were received from LightWave. This image data is unaffected by the display settings.

Copy   c
Copy the screen version of the current image to the Windows clipboard. Once copied, you can switch to any program that supports 24-bit RGB and 8-bit indexed color BMPs on the clipboard and paste the image there. If the alpha channel is currently being displayed in QV, it's copied as an 8-bit grayscale image. Otherwise the full color image is copied.
Print   p
>Print the screen version of the current image at 100 DPI. If the image is larger than the printable area reported by the printer driver, it's scaled to fit. Prints the alpha channel if that's displayed, otherwise prints the RGB image.

Caution: Using a parallel port printer attached to the pass-through of a parallel port LightWave hardware key may deprogram the key. Contact NewTek to exchange your old parallel port hardware key for a USB key, or install a separate parallel port for your printer, or use an A/B switch.

Delete   d or Del
Discard the current image from QV's memory. If this image is the only one QV can display, QV's window closes.
Channels   i, a, r, g, b
>Display the full color image or one of the image channels (alpha, red, green, or blue). The keyboard shortcuts toggle between displaying the specified channel and displaying the full color image.
Hot Pixels   h
Show the hot pixels, those that encode to illegal analog NTSC or PAL video signal levels. Hot pixel thresholds for the composite and chroma components of the signal can be specified on the Hot Pixels tab of the Notes and Settings dialog.
Safe Outlines   f
Show video safe and text safe outlines, or a rectangular outline with an aspect and margin you define on the Borders tab of the Notes and Settings dialog.
Adjust Window   j
Centers QV's window and resizes it to fit the current image. If the current zoom amount makes the image too large to fit on the screen, the zoom is adjusted to the largest value that allows the image to fit.
Notes and Settings   n
Opens the Notes and Settings dialog. You can rename the image (the image name is the default filename when the image is saved) and jot notes about it. The render time is displayed here. Pressing the Scene Info button adds a settings summary to the notes edit field containing most of the information displayed in LightWave's Render Status dialog. The Notes and Settings dialog also has tabs for changing the way the image is displayed.
Text   t, u
Add or undo text. When adding text, the mouse cursor changes to an I-beam, and the position of your mouse click becomes the anchor point for the text. QV then opens the Add Text dialog, where you can type the text to draw and set the font characteristics. After adding a line of text, you can undo (and redo) the text.

Config File

QV maintains your default settings in a config file named qv4.cfg. This file can be located in several different places in your file system. QV looks for it in

  1. the content directory
  2. the LightWave Settings directory
  3. the directory in the Windows USERPROFILE environment variable
  4. the directory where qv.p resides

The Windows USERPROFILE directory is the default location for user-specific settings, typically Documents. The LightWave Settings directory is the directory where LightWave's config file (lw3.cfg) resides. By default, this is the same as the USERPROFILE directory, but you can change this on the LightWave command line using the -c switch.

The first time you run QV, you won't have a qv4.cfg. QV will create one in the directory where qv.p is and will find it there the next time it runs. You don't need to do anything to make this happen, and you may find this is entirely sufficient.

But you might want to have different defaults for different projects or users. To do that, just copy the qv4.cfg that QV makes into the content directory, the LightWave Settings directory, or the USERPROFILE directory (or any combination of the three), and change the defaults within QV the next time it's invoked for that project, LightWave config or user.

Memory Usage

All render displays consume some memory for image storage, and this can become a concern if you're working near the limits of your system's memory capacity. QV needs a total of 20 bytes per pixel to store the floating-point and screen versions of each image.


QV displays an About dialog when you select QV40 as the current Render Display on the Render Options panel. The About dialog includes a build date for the qv.p file. This tells you which revision of qv.p you're running.

January 21, 2009
A bug in QV caused LightWave to crash on exit when QV was first installed. Although only reported for the 64-bit version, the underlying cause has been fixed in both the 64-bit and 32-bit versions. Thanks to Michael Struck for reporting the problem and testing the fix.
January 16, 2009
QV goes 64-bit! Thanks to Michael Wolf for compiling the x86-64 version and for cleaning up the x64-unfriendly bits of source code.
July 5, 2006
QV's automatic dismissal of LightWave's Render Status panel can now be disabled. After running and exiting LightWave at least once with this build of QV, load QV's config file, qv4.cfg, into a plain text editor and change the 1 to a 0 in the line reading
  CloseRenderStatus 1
June 20, 2006
QV wasn't handling very large pixel values correctly. Using the default white and black points (1.0 and 0.0), pixels with levels greater than 8421504.5 (8.4 million) were clipped to black rather than white. When displaying floating-point pixel values in the status bar, values greater than 1000000.0 (1 million) overflowed the display's text buffer, which could cause a crash. These have been fixed, and the formatting of the value text has been improved.

Also, because the name of the Render Status window in LightWave 9.0 has changed, this build of QV takes some additional steps necessary in 9.0 to find and automatically close it. Thanks to Ken Nign for discovering and reporting these issues and for testing the new build.

September 2, 2005
Some people reported that the .zip file of the August 27 build was corrupt. The file itself was OK, but it appears that, merely by chance, it contained a sequence of bytes that triggered EOL (end-of-line) translation during downloading, something that should only happen to text files. By slightly swizzling the source code, I've produced a .zip file that doesn't do this.
August 27, 2005
The frame number has been added to the information displayed on the Notes tab of the Notes and Settings dialog. It's now the first line of text added to the Notes field by the Scene Info button. Thanks to Mitch Rosefelt for pointing out the usefulness of this information.
August 1, 2005
After the initial release of QV 4 (build date June 9, 2005), two bugs were found.
  1. If your task bar was anywhere other than at the bottom of your desktop, QV's window would open at strange sizes and positions.
  2. QV didn't load all of the settings in its config file.

These have been fixed. Thanks to James Jones and Panikos Christophorou for finding them and testing the update.