Me too I've thought to gamma issues, but in 3dsmax I've plaied with all possible combinations: I've switch On gamma, tried off, tried with different gamma values, tried to play with Vray Color Mapping but nothing...

About Post-Fx Option, this is the screenshot of Vue Standalone:
http://www.ossosso.com/public/scambio/03_vue.jpg

I've noticed that if I select the "main Camera" in 3dsmax (xStream version) and I click on "Edit Object" button, I can change the "Auto-Exposure" parameter, and other like "Gamma Correction", "Natural film response"... but effectively it haven't any effect on the final image, so I assume that the xStream version blocks in some way the "Advance Camera Options".

Is there any other way to apply Post-FX Options on the xStream version?

mmm.. I've left all by default,
Display Unit: Metric (automatic)
Internat Unit: 0.1 Meterd

The strange thing is that if I paint till 6 trees it displays just dots, the 7th is displaied correctly also the 14th 21st and so on...

If I click on the "View DIsplay Options" on the top right side of each viewport and I switch to "Wireframe Box", the problem persist.

what can I do?

Thank you for your answers