SolidWorks (*.sldprt, *.sldasm): SolidWorks Part and Assembly files.

Stereo Lithography .STL (.stl): STL files are typically used for rapid prototyping in CAD programs. It is a simple, triangle-based format.

TrueSpace (*.cob, *.scn): The file format used by Caligari TrueSpace.

USGS DEM (*.dem) United States Geological Survey (USGS) digital elevation model (dem) files. Many 3D landscape files are available in this format on the Internet.

WaveFront (*.obj): WaveFront OBJ (object) files are used by WaveFront's Advanced Visualizer application to store geometric objects composed of lines, polygons, free-form curves and Surfaces.

VRML 2.0 (*.wrl)/VRML 97(*.wrl) VRML is short for Virtual Reality Modeling Language and is actually a specification for displaying 3-D objects on the Internet. The reason that there are two importers is that the first one comes from Okino while the second one is developed in-house which has the ability to import keyframes. 

XGL/ZGL (*.xgl, *.zgl): XML-based transfer file format, exportable from a number of popular CAD applications.

      当然，也可以用Deep exploration这款软件来导的，这个是美国一家公司开发的，EON和VT都用这个来进行了下二次开发。通过这款软件，我们可以打开绝大部分3D/CAD软件的文件，然后可以在上面附材质，压缩面，合并Object等等，最后可以导出成EON和VT的专属格式（当然，要完成最后这一步，我们需要先装EON或者VT的插件才行）

      不过，大部分的情况下，我们做的内容对材质都有点要求的，稍微打点颜色，删除些不必要的物体，对模型优化优化等等，所以，对于真正去做一个虚拟现实内容的时候，我们都会将CAD文件导入到MAX中，或者甚至是直接在MAX中重做模型。

      呵呵，当然啦，如果是做实验、研究之类或者是交个论文报告什么的，就不需要这样的，对视觉效果没什么要求，直接导入或者用Deep exploration导入都行。