Hi Paolo,

> I use the curves and the planar command in moi3d to make virtual friskets in Artrage.
> It would be helpfull if i could see the Artrage canvas through the Moi3d viewport.
> When i have finished the job in Moi,then i use copy-paste to place the result in Artrage.

You could do that by taking a snapshot of the Artrage canvas and saving it as an image file, and then bringing that image file into MoI as a background image, using the View > Image command:
http://moi3d.com/2.0/docs/moi_command_reference5.htm#image


> Question : Is it possible to make the viewport transparent (like a alpha channel color),
> but not the cuves.

No, there's no mechanism for making the viewport transparent in such a way as to actually expose totally separate application windows behind the MoI window - but the background image mechanism is set up so that you can place an image as the background of the viewport and have your curves drawn on top of it.

Basically the tracing mechanism in MoI is oriented towards tracing over an image, not for tracing over separate running applications. So you need to take a snapshot of your other application and put it into an image file to get what you are asking here - once it is in image form then you can use the background image mechanism for tracing over it.

- Michael