A progressive applet is used to download and display a small image ahead of the full Blaze player.

This is useful because it causes the blank applet window, or the Sun Java sunflower, to be cleared quickly. The image will remain displayed until the Blaze 3D presentation is completely downloaded. The image can be joined seamlessly into the main movie. For example, you could display an image of frame 1 of your movie.

To deploy a progressive applet, also known as a preloading applet, you need an additional jar file. This will be created by Blaze 3D Studio when the 'Use progressive applet' option on the HTML tab is selected. When 'Create HTML' is pressed, preload.jar will appear in your project directory.

The progressive applet also requires changes in the HTML Applet tag. These are written into the HTML generated automatically by the Studio when 'Use progressive applet' is selected. The differences from the standard applet tag are highlighted below:

   <applet archive=preload.jar,holomatix.jar code=preload.class width=550 height=400 align=&quot&quot MAYSCRIPT>
      <param name="movie" value="my3dProject.swf">
      <param name="imagefile" value="loading.jpg">
    </applet>

The three changes required are:

• Specify preload.jar in the archive parameter of the applet tag, in addition to holomatix.jar. It must be the first file specified, ensuring that it is downloaded before holomatix.jar.
• Specify preload.class in the code parameter of the applet tag. blaze3d.class should not appear at all.
• Add an extra applet param tag whose name is 'imagefile' and whose value is the name of the image that should be displayed.

Finally, you need to create an image that will be displayed until the main player is downloaded. This will usually be identical to the first frame of your movie. You could create it using the video tools in Blaze 3D Studio. Both .gif and .jpg formats are supported by preload.jar. The file size of the image determines how long the user will have to wait until the image is displayed so it should be kept as small as possible.

The image file must now be inserted into preload.jar. The easiest way to acheive this is to rename preload.jar to preload.zip, then drag the image file onto preload.zip. It will be inserted into the zip file. Rename preload.zip back to preload.jar.

If no image file is inserted, preload.jar will clear the applet with the background colour of your top-level movie.

To deploy the progressive applet files, you should take care to copy the changes to the applet tag from the auto-generated HTML into the HTML page where the applet will finally appear. You must upload preload.jar to the same directory as holomatix.jar. All othe files should be treated as for a normal deployment.