Inventor Hints

• UGCS now sends the correct mime type for iv/vrml files, so you can view your meshes stored on ugcs from Netscape. (If you store your files on some other cluster and Netscape shows them as plain text, ask your sysadmin to add the mime types x-word/x-vrml (extensions wrl, vrml) and graphics/x-inventor (iv))
• Webspace, the sgi viewer for vrml has no problem viewing vrml files, inventor files, jpg textures (you can convert your .rgb texture to jpeg to make it smaller). It can download files through the net (you can specify an URL as file name), and it can even view gzipped files. (Though if you put a gzipped file on the web, the extension will be .gz so httpd will send a binary mime type instead of vrml, so Netscape will try to ftp it instead of viewing it in Webspace. If you find a way around the extension problem, please tell me.)
• Inventor has a binary format (a mesh file in binary format seems to take half the space of its equivalent in ascii). To convert between formats use ivcat (see man page)
• There is a more efficient way (both in terms of space and SPEED) of giving triangle meshes than IndexedFaceSet, and that is IndexedTriangleStripSet. Example: IndexedTriangleStripSet { coordIndex [ 0, 1, 2, 3, 4, -1, 10, 11, 12, 13, -1 ] } will draw 5 triangles between the points with coordinate indices (0,1,2) (2,1,3) (2,3,4) (10,11,12) (12,11,13).
• If you find your meshes to have a lot of noise (surfaces look rugged when they should be smooth) try to apply a low-pass filter to your point data (replace the coordinate of each point with an average of the old coordinate and the coordinates of all the close neighbors. Say you have a point X5 which is "close" to 6 of its 8 neighbors: X2, X4, X6, X7, X8, X9. Then you would set the new coordinate of point 5 to 0.5*X5+ 0.5*(X2+x4+ X6+ X7+ X8 + X9)/6 ) Try to play with the weights (if your filter is too aggressive, you might lose some high-frequency details in your mesh).
• If you use the straight coordinates X,Y and Y for your mesh, you may find out that the final viewed surface is rotated by pi about the x axis. This is due to the fact that inventor works with slight different coordinate system. To cope with that problem, you may want to add a rotation command line in front of your mesh: Rotation { rotation 1 0 0 3.1415926535 }