Re: [Flightgear-devel] Propellor graphics
Update to my own comments: Julian Foad wrote: The spinning propellor (on c172-3d) needs a bit of work. It spins even when the model is parked and the engine stopped. If pause mode is on, it spins more slowly but still does not stop. That works now (it stops). Maybe I didn't have that recent fix (in JSBSim). With magnetos off but starter engaged, the tachometer shows about 600 RPM (i.e. 10 revs per second). The propellor spins at one and a bit revs per second. I think the propellor is supposed to be directly driven from the engine crankshaft, but I'm not sure. Still wrong, but not David's fault. Due to mis-use of update(multi_loop) - see separate message. The two blades are not twisted relative to each other: one blade is pushing and the other pulling. David has fixed this. The transparency feature is not working for me, so the propellor disc suddenly appears as an opaque object. I have applied David Megginson's plib-smoothing.dif and my plib (from CVS) already appears to have the equivalent of the transparency patch. I had two copies of plib installed - oops! Transparency and smoothing are now working for me. The disc that fades in at higher speeds is solid grey for me. It needs to have a (radial) colour profile that matches the blades, i.e. mostly black with some red bits. The expected grey appearance will come automatically when a partially transparent black disc is displayed over a light background (sky etc.). Apologies - it looks pretty good as it is, both in sunlight and at night, now that I see it as intended - i.e. very feint, so the colouring of it is not too important. In fact, the light grey colour of it looks like a highlight reflection off the blades. The only situation in which it goes wrong is in an external view, it cuts out the cloud texture (so it looks like a solid grey disc) - but ground textures show through it perfectly, and both ground and clouds show through properly in the pilot's eye view. Is there a way to make the prop fade out and the disc fade in as RPM changes? Something like animation type=transparency ? I tried making the propeller material transparent in the .ac file, and that works except that behind a transparent propeller blade, the clouds and some parts of the airframe disappear (engine cowling, tail fin, ...) while the rest remains (seats, wings, ...). Yet behind the disc, the whole of the airframe is OK and only the clouds disappear. OK, I'd better step back from 3D modelling. I've never done it and this seems to be one of those tricky areas that you modellers learn about. - Julian ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
Julian Foad writes: Apologies - it looks pretty good as it is, both in sunlight and at night, now that I see it as intended - i.e. very feint, so the colouring of it is not too important. In fact, the light grey colour of it looks like a highlight reflection off the blades. The only situation in which it goes wrong is in an external view, it cuts out the cloud texture (so it looks like a solid grey disc) - but ground textures show through it perfectly, and both ground and clouds show through properly in the pilot's eye view. Is there a way to make the prop fade out and the disc fade in as RPM changes? Something like animation type=transparency ? I tried making the propeller material transparent in the .ac file, and that works except that behind a transparent propeller blade, the clouds and some parts of the airframe disappear (engine cowling, tail fin, ...) while the rest remains (seats, wings, ...). Yet behind the disc, the whole of the airframe is OK and only the clouds disappear. In other systems, I've seen something implimented called 'fade level of detail'. It's a pretty nifty thing. They idea is that instead of popping from one LOD to the next, you blend from one to the next over a distance using a transparency applied to one LOD and (1 - transparency) applied to the other. It would take some thought to impliment well ... especially if the models have transparent components. But, if people have implimented it already, it may not be that hard to do ... Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Cities[EMAIL PROTECTED] [EMAIL PROTECTED] Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
re: [Flightgear-devel] Propellor graphics
Julian Foad writes: It spins even when the model is parked and the engine stopped. If pause mode is on, it spins more slowly but still does not stop. This was fixed in JSBSim a week or so ago -- unless something else has undone the change, try updating to the newest FlightGear CVS. The model just shows what the FDM is reporting. The two blades are not twisted relative to each other: one blade is pushing and the other pulling. Yes, that needs to be fixed, but I'm still trying to understand it (even my own preflight inspections of a real C172 prop aren't helping me yet). The transparency feature is not working for me, so the propellor disc suddenly appears as an opaque object. I have applied David Megginson's plib-smoothing.dif and my plib (from CVS) already appears to have the equivalent of the transparency patch. Are you sure you have installed the new plib and linked with it? Is anyone else using the newest CVS plib getting an opaque propeller disk? Thanks, David -- David Megginson [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] Propellor graphics
On the C172s I've used, the prop starts about as fast as a car engine, i.e. in well under a second. It would be hard to get a tach reading, but I'll try to remember. Would you get the same cranking speed if you cranked the engine with the magnetos off? It would certainly stop the engine starting. Richard Bytheway ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] Propellor graphics
I agree that this was how it was originally coded, but something has changed in the last week or so and the propellor definitely spins an order of magnitude slower than reported rpm. Did someone get rps and rpm mixed up?? ;-) smime.p7s Description: application/pkcs7-signature
re: [Flightgear-devel] Propellor graphics
Jim Wilson writes: Yes, that needs to be fixed, but I'm still trying to understand it (even my own preflight inspections of a real C172 prop aren't helping me yet). If you look down at the propeller in the model from above (with the nose appearing pointed up on the screen), the blade on the right is fine. The top edge is trailing. The blade on the left's top edge should be leading, but as it is now it is also trailing. The problem turned out to be very simple. I originally had the propeller modelled correctly, but during some reworking, I copied one blade to the other and ended up reversing the incidence angle of the blade. That's why I couldn't understand what everyone was complaining about -- when I actually looked at the propeller in Blender on a high magnification, it was obvious what had happened. A new checkin is on the way. All the best, David -- David Megginson [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
On Thu 18. April 2002 13:17, you wrote: Yes, I think the tach probably should only read 100-200 rpm while the engine is cranking, before it catches. Maybe Alex (or David) could watch this on their next flight? On the C172s I've used, the prop starts about as fast as a car engine, i.e. in well under a second. It would be hard to get a tach reading, but I'll try to remember. Yes, the propellor spins way to slowly compared to engine rpm. This might be intentional so that it maintains 'smooth' animation. But, it is maybe just a little noticably too slow ... Actually, the propeller spins at *exactly* the reported RPM. The trouble is that you see only snapshots of its position as determined by framerate, and the positions are usually creeping one direction or another. David you can inspire by this photos. This propeller is gray with yelow tips http://musicabona.com/martin/pic/tocna30.JPG This you can see on taxiing ie 1000 RPM The clouds could rotate as it rotates now. The propeller itself you can see only when motor is stop or turned by starter. So we need at least 3 steps. http://musicabona.com/martin/pic/tocna01.jpg This is on start ie 2500 RPM Notice the yelow transparent circle from tips and in the middle is nearly nothing. http://musicabona.com/martin/pic/tocna22.jpg I have also some advice on making textures for your model. You have done it very good so please be free to copy it to /dev/null. I suggest you to make background of textures white,black or transparent but please not yellow. It is good for debugging but not for use. You can make better glass texture when you start on some white - blue - green color and only add transparency. I don't know how it looks with shading, but IMHO it should be better to make propeler disc like two cones than 1 cylinder. Also there are some strange artifacts on the wing tips. Regards, Madr -- Martin Dressler e-mail: [EMAIL PROTECTED] http://www.musicabona.com/martin ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
From: David Megginson [EMAIL PROTECTED] magnification, it was obvious what had happened. A new checkin is on the way. You forgot to correct your model to avoid the cutting propeller disc ! -Fred ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
Frederic Bouvier writes: You forgot to correct your model to avoid the cutting propeller disc ! What do you mean, exactly, by a cutting disk? All the best, David -- David Megginson [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
Frederic Bouvier writes: What do you mean, exactly, by a cutting disk? We can see the interior of the c172 when viewing the front of the plane in the external view Right -- I forgot to edit the ac file. I'll check in the fix right now. All the best, David -- David Megginson [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Propellor graphics
The spinning propellor (on c172-3d) needs a bit of work. It spins even when the model is parked and the engine stopped. If pause mode is on, it spins more slowly but still does not stop. With magnetos off but starter engaged, the tachometer shows about 600 RPM (i.e. 10 revs per second). The propellor spins at one and a bit revs per second. I think the propellor is supposed to be directly driven from the engine crankshaft, but I'm not sure. The two blades are not twisted relative to each other: one blade is pushing and the other pulling. The transparency feature is not working for me, so the propellor disc suddenly appears as an opaque object. I have applied David Megginson's plib-smoothing.dif and my plib (from CVS) already appears to have the equivalent of the transparency patch. That bug may be the only reason for the following observation: The disc that fades in at higher speeds is solid grey for me. It needs to have a (radial) colour profile that matches the blades, i.e. mostly black with some red bits. The expected grey appearance will come automatically when a partially transparent black disc is displayed over a light background (sky etc.). But nevertheless it is a nice fun, eye-catching feature. - Julian ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
Julian Foad writes: The spinning propellor (on c172-3d) needs a bit of work. It spins even when the model is parked and the engine stopped. If pause mode is on, it spins more slowly but still does not stop. For me, the propellor does stop completely. With magnetos off but starter engaged, the tachometer shows about 600 RPM (i.e. 10 revs per second). Yes, I think the tach probably should only read 100-200 rpm while the engine is cranking, before it catches. Maybe Alex (or David) could watch this on their next flight? The propellor spins at one and a bit revs per second. I think the propellor is supposed to be directly driven from the engine crankshaft, but I'm not sure. Yes, the propellor spins way to slowly compared to engine rpm. This might be intentional so that it maintains 'smooth' animation. But, it is maybe just a little noticably too slow ... The two blades are not twisted relative to each other: one blade is pushing and the other pulling. I've mentioned this to David M. before, but I'm not sure I communicated this well. He really needs to take a look at a real prop and visualize how it pushes the air as it turns. One of the blades of the prop is definitely angled 'backwards.' The transparency feature is not working for me, so the propellor disc suddenly appears as an opaque object. I have applied David Megginson's plib-smoothing.dif and my plib (from CVS) already appears to have the equivalent of the transparency patch. That bug may be the only reason for the following observation: The disc that fades in at higher speeds is solid grey for me. It needs to have a (radial) colour profile that matches the blades, i.e. mostly black with some red bits. The expected grey appearance will come automatically when a partially transparent black disc is displayed over a light background (sky etc.). You need to upgrade to the latest cvs-plib to get a transparent prop. David found a bug/limitation in plib when he was trying to impliment a semi-transparent prop disk. Unfortunately it's there in the stable 1.4.x releases. But nevertheless it is a nice fun, eye-catching feature. Yes, David did a very nice job on his first crack at it. A few more little tweaks and it will 'perfect.' :-) Regards, Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Cities[EMAIL PROTECTED] [EMAIL PROTECTED] Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Propellor graphics
Curtis L. Olson wrote: Yes, the propellor spins way to slowly compared to engine rpm. This might be intentional so that it maintains 'smooth' animation. But, it is maybe just a little noticably too slow ... Actually, I think this is a recent change. I remember doing some back of the envelope (er, wristwatch, in this case) work to verify the speeds when the feature first went in, and the speed looked pretty much correct. But in current code, it's slow; maybe an extra factor of something or other got added? Andy -- Andrew J. RossNextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com Men go crazy in conflagrations. They only get better one by one. - Sting (misquoted) ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
