FSUIPC and Motion Platforms

[IanH1960]

Hi Pete,

I'm interested in investigating using fsuipc to pull data from fs9 to drive a motion platform. I have some experience of using FSConnect to do this and have run into problems with the data extraction rates - pulling 6 "double" data items (3 velocities and 3 angles) takes about 250ms on my set up. Can you tell me if I might expect substantially faster data extraction rates if I use fsuipc to do this?

I am using an effective alternative approach which is currently yielding approx 60ms cycle times to read and process an equivalent of the 6 data items but the range of data items available is more limited than that available from fsuipc.

I can do additional processing if necessary eg is it possible to pull a "block" of data out with a single call which can them be further processed by the external app to yield individual data items? Just pondering.

Thanks,

Ian

[Pete Dowson]

I'm interested in investigating using fsuipc to pull data from fs9 to drive a motion platform. I have some experience of using FSConnect to do this and have run into problems with the data extraction rates - pulling 6 "double" data items (3 velocities and 3 angles) takes about 250ms on my set up. Can you tell me if I might expect substantially faster data extraction rates if I use fsuipc to do this?

250 mSecs? Phew! What's FSConnect doing to take that long? Even if you run across a WideFS connection you should easily be able to match FS frame rates of 20-30fps. And it certainly isn't related to the amount of data being "pulled", unless you are talking about substantially bigger blocks, like 1kb or more. 6 x 64bit double floating point values is nothing.

Maybe it forced to to request them all separately? With FSUIPC your actual inter-process interface is one call for each block of data no matter how many entries, up to 32kbs worth of data.

I can do additional processing if necessary eg is it possible to pull a "block" of data out with a single call which can them be further processed by the external app to yield individual data items? Just pondering.

That's all done for you. Why not download the SDK and check it out?

Regards

Pete

[AndyT]

You might also want to look over on http://www.mycockpit.org since some of us are working on an open source software for driving motion platforms.

[IanH1960]

Thanks Pete,

I bought a key and registered my fsuipc.

I've had to port a core set of the API to the scripting language I'm using for the motion driver software but you are right. I'm now seeing data loop speeds of about 40ms with fsuipc and that's with a 20ms sleep inserted after the fsuipc process call and pulling a set of 7 data times each time. It's fast.

I should have checked before I registered my copy but I assume that in the first instance my external program will not be able to access fsuipc unless it is a registered copy?

Thanks again,

Ian

[Pete Dowson]

I should have checked before I registered my copy but I assume that in the first instance my external program will not be able to access fsuipc unless it is a registered copy?

No, you didn't have to register to gain such access. Registration pays for all the user facilities, not application access.

That said, there used to be an application key check before access was allowed, which was waived for registered users. Freeware applications got a free key for access even with unregistered copies, whilst publishers of commercial applications negotiated for a license. The latter still applies, but the key checking was becoming a real nuisance so, since FSX was released, I discontinued it in both FSUIPC3 and FSUIPC4.

I always encourage developers to register, however, as it is a small recompense for time spent in providing the SDK updates and additional support. So thank you very much! ;-)

Regards

Pete

[IanH1960]

You're welcome, it's a small price to pay for the functionality it brings.

Ian

[AndyT]

Hi Pete,

I'm also working on a motion platform. I've downloaded the SDK from your website but it says its for pre-FSX sims. I'm building for FSX. Will this be a problem? Do you have a new SDK for FSX?

Thanks

[Pete Dowson]

I'm also working on a motion platform. I've downloaded the SDK from your website but it says its for pre-FSX sims. I'm building for FSX. Will this be a problem? Do you have a new SDK for FSX?

That one is applicable, but there is more information in the FSX downloads Announcement above. always scan the Announcements! They Announce things! ;-)

Regards

Pete

[AndyT]

Thanks Pete.

I thought I had read all of the announcements. I guess not.