Hi there …
i want to know can i export a variable from unity to VB.net ?
you can not use unity inside of anything
unity is standalone, its no technology to embed nor is it a .net technology actually, .net is only the scripting layer
as for using vb.net inside of unity: if you build .net assemblies you can use them in unity but only with the 3 languages offered by unity
Well actually you could embed Unity, i’ve done it with Director using the webplayer activeX component and if I remember correctly was able to communicate both ways via javascript or some web browser messaging system.
No idea about doing that in VB.Net though and this was probably back with 2.6 so no idea if anything has changed since then.
yes thats possible but thats not really embedding in the sense he asked cause he will not be able to access anything within the engine it all has to go through the webform → javascript bridge forth and back so through like 5 layers on each variable request
lol - funny that’s exactly what I thought ‘embedding’ would have meant 
In the case of passing variables then couldn’t you just set up a net socket to do the communication?
Guess the OP needs to be a bit more specific to his requirements.
TL;DR - Give us more info on what you want to do.
Normally when you use .NET or anything embedding means that you just ‘drop in the library’ and use it.
But Unity is no SDK for such usage, its not even a .NET technology actually and its plugin functionality does not realistically allow interfacing with it on native code base either.
That likely would be what you would use, though not needfully net sockets, I would go with pipes. Sockets might have troubles with funny security software.