How To...

Convert 3D Models to MDL Format

AGI has a conversion program that allows you to convert Lightwave (.lwo) format files to an MDL model. If you have built your model using something other than Lightwave you will have to first convert the file to .lwo format before you can convert it to an MDL model.

Some file formats can be imported directly into Lightwave and then saved or exported in the Lightwave format. Also, many 3D software packages can save or export files in the Lightwave format. Check your 3D modeling software documentation to find out if it supports these features.

There are also 3rd party utilities that will allow you to convert 3D models to the Lightwave format. They include:

Converting to an MDL Model

  1. Using any of the above mentioned methods save or convert your 3D model to the .lwo format.

  2. Download the Lightwave to MDL Model Converter (LwConvert) from the AGI website here.

  3. The converter is a single .exe file, that can be installed anywhere on your hard drive (typically, C:\Program Files\AGI\LwConvert.exe). When you run it, a dialog box appears.

  4. Use the browse buttons to select the .lwo file to convert and to select the destination for the .mdl file.

  5. Use the Model Type buttons to select which type of model you are converting (or the closest fit). In Lightwave (all versions), +Y is considered "up," and in Lightwave (6 and up), +Z is considered "front." In STK/VO 4.1.x, an aircraft uses -Z as "up," but a facility uses +Z for "up." The converter will attempt to compensate for these kinds of differences if you tell it which type of model you are converting.

  6. Select Apply if you are going to convert more models or OK to convert the model and close the utility.

  7. Review technical tips and more useful information on model conversion by selecting the Hints button.


Keep in mind that MDL only supports a small subset of what Lightwave is capable of rendering. This is because Lightwave can take its time to process each animation frame, sometimes taking an hour or more per frame, whereas STK will attempt to render your model in realtime, and make it interactive with the user. For this reason, it is recommended that you use far fewer polygons in MDL files than you would for a Lightwave-rendered animation.

Generally speaking, if you make your model look good in Lightwave's built-in preview window, then the model stands a good chance of converting nicely. The preview window uses OpenGL for rendering, as does STK. So, the converted model may look more like the preview window than a finished Lightwave-rendered image.