I imported 3ds model to gmax...but some polygons are visible and others are not. I found that the reason is polygon's normal property(in this forum. :-)) I have to flip invisible polygons to make visible.But my 3ds model has too many polygons so I can't flip polygonsone by one. How can I flip invible polygons?I used double sided texture but it didn't work. :-(

Try going in the modifier stack, selecting Normal and Unify Normals properties, That worked for me almost in the 95% of a model that I imported from a 3ds.

thanks for your reply...but I still have many invisible polygons..After applying normal modifier, how can I remove them?

Try this tutorial, that I found on my 3ds book that also apply for gmax. Ignore the reference about the CD and the model they talk about here, This is how I did it:To fix the normals on an imported mesh model, follow these steps:1. Open the Hailing Taxi.max file from the Chap 12 directory on the CD-ROM.2. Select the problem object

Thanks for your reply again! But it seems that it works only in 3ds and is impossible in gmax. Maybe because I'm beginner....:-)3. In the Selection rollout, select the Show Normals option and set the Scale value to a small number like 0.1.-> I can't find normals option and scale value. Where is it? When I apply normal modifier, there is only two options : flip and unify.4. With the element subobject still selected, click the Unify button in the Surface Properties dialog box and then click the Flip button until all normals are pointing outward.-> I click flip button but polygons switches only....

Dont worry, gmax is not very user friendly, and some of the menus are really hard to see, I have attached a screenshot for you to check.

Thanks for your kind replies!! But unfortunately I found that it's not the normal or flip problem. :-) Your tutorial helps me a lot. Thanks!