Re: [Flightgear-devel] Sky dive free fall
Curtis Olson wrote: Has anyone developed a more detailed model of a sky diver? I'm especially interested in the free fall phase. (My brother is up to his 38th jump now I think.) I most certainly have! Have you looked at bluebird or my other shuttlecraft?? (which for the moment are more up to date) The free fall stage is carefully modeled with physics and formulas in mind. To see drag constant for spread eagle, and time to reach terminal velocity, etc. etc. Look at Nasal/walk.nas and search for eagle Stewart http://seahorseCorral.org/flightgear_aircraft.html -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
Curtis Olson wrote: An accurate FDM would be immensely complex considering all the possible poses a human can achieve. But perhaps something simplistic could be worked up using the arms and legs as control surfaces. My focus right now is not so much getting accurate free fall dynamics, but to get a nice jumper model and then just hack up some sort of dynamics with approximately the right lift/drag ratio for someone is a stable free fall pose. The goal would be to get approximately the right fall rates and timings so that there is training value in solving problems and overcoming various combinations of faults with in a realistic time frame. It's still only a very partial simulation but hopefully a step better than just sitting around in a circle talking through various scenarios. I have the jumper with animations already in bluebird. You can even edit the animation to see Waldo (walker/jumper) do more visually. Getting more accurate variability in free fall physics is an idea I tagged as difficult and low priority. Because I could not get an entire FDM in Nasal to accurately place the jumper's position, due to low frame rates causing an uneven result. I fixed the formulas on when the jumper exits the aircraft, and when the parachute is opened. From those two variables, I made the entire jump work off of a set of formulas for the stages: accelerate to free fall, free fall in spread eagle, pull chute cord, and float to ground. To be able to get Waldo to change velocities and positions in free fall would be a next step goal, but would probably need a separate FDM outside of nasal. Or if it Can be done in Nasal, some approach that exceeds the limitations I encountered. For adding Waldo to other aircraft, I did work up a Walker addition patch a few months ago for Anders balloon. It is still available for any interested aircraft owners. Stewart http://seahorseCorral.org/flightgear_aircraft.html -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
On Sun, May 31, 2009 at 9:38 AM, S Andreason wrote: Curtis Olson wrote: Has anyone developed a more detailed model of a sky diver? I'm especially interested in the free fall phase. (My brother is up to his 38th jump now I think.) I most certainly have! Have you looked at bluebird or my other shuttlecraft?? (which for the moment are more up to date) The free fall stage is carefully modeled with physics and formulas in mind. To see drag constant for spread eagle, and time to reach terminal velocity, etc. etc. Look at Nasal/walk.nas and search for eagle Stewart http://seahorseCorral.org/flightgear_aircraft.html Hey, that's pretty neat (the bluebird is part of CVS if anyone else wants to play.) Question, is there a way to turn the walker? I found forward/back and left/right but he always faces the same direction. Regards, Curt. -- Curtis Olson: http://baron.flightgear.org/~curt/ -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
Josef Duschl wrote: Why not start by look for skydiving gps tracks on the net to come up with a model? Hi Josef, I didn't think gps was meant to be as accurate on the z-axis. It is all physics anyways. I can draw a smooth curve with the right formula. Here is a link to one of the better ones I found: http://www.pha.jhu.edu/%7Ebroholm/l10/node5.html Stewart -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
Curtis Olson wrote: Hey, that's pretty neat (the bluebird is part of CVS if anyone else wants to play.) Question, is there a way to turn the walker? I found forward/back and left/right but he always faces the same direction. Hi Curtis, When in Walk View, mouse mode 2 (view direction), panning the view changes Waldo's heading. When in Walker Orbit View, Waldo stays put, and you can pan the camera around your walker/jumper. Stewart -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
I don't see much of a problem with a suitable jumper. Making it a ballistic object with drag and mass would be easy. But a more realistic FDM . Hmmm Vivian -Original Message- From: Curtis Olson [mailto:curtol...@gmail.com] Sent: 30 May 2009 16:25 To: FlightGear developers discussions Subject: [Flightgear-devel] Sky dive free fall I know we have a few aircraft that can drop sky divers. The Noratlas was the first one I recall. However, these sky divers immediately pull their chutes and drift down ... and the skydiver/chute model is very simplistic ... optimized to be viewed from the drop plane and optimized to have bunches of these in the sky at one time. Has anyone developed a more detailed model of a sky diver? I'm especially interested in the free fall phase. (My brother is up to his 38th jump now I think.) A detailed jumper with articulated arms and legs (even with just a cannon ball FDM to start out with) could be the start of an interesting training tool. My brother speaks of some of the training classes he has gone to where different failure scenarios are presented, but you are sitting (or perhaps lying) on the ground with no real urgency (except some false urgency of the instructor yelling at you.) If some of these failure cases could be cooked into a FlightGear scenario with a free fall sky diver, there could be some good virtual urgency and good training value so students can instinctively learn the right things to do in various scenarios without forgetting key steps or key aspects of the situation. I know we have some nice pilot figures that people include in some of our aircraft. How hard would it be to develop a nicely detailed sky diver model that can be posed in typical free fall positions? Thanks, Curt. -- Curtis Olson: http://baron.flightgear.org/~curt/ -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
On Sat, May 30, 2009 at 12:02 PM, Vivian Meazza wrote: I don’t see much of a problem with a suitable jumper. Making it a ballistic object with drag and mass would be easy. But a more realistic FDM … Hmmm An accurate FDM would be immensely complex considering all the possible poses a human can achieve. But perhaps something simplistic could be worked up using the arms and legs as control surfaces. My focus right now is not so much getting accurate free fall dynamics, but to get a nice jumper model and then just hack up some sort of dynamics with approximately the right lift/drag ratio for someone is a stable free fall pose. The goal would be to get approximately the right fall rates and timings so that there is training value in solving problems and overcoming various combinations of faults with in a realistic time frame. It's still only a very partial simulation but hopefully a step better than just sitting around in a circle talking through various scenarios. The next step would be to have a canopy that could be configured to have various problems opening up and be able to draw that somehow from the perspective of the sky diver, and perhaps have some appropriate dyanmics for partially tangled or partially inflated chutes? Obviously there's endless variabiltiy and high fidelity in all respects would be crazy to try to achieve, but it would be interesting to take a few small steps forward and see how far we can get. Best regards, Curt. -- Curtis Olson: http://baron.flightgear.org/~curt/ -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
On Saturday 30 May 2009, Curtis Olson wrote: On Sat, May 30, 2009 at 12:02 PM, Vivian Meazza wrote: I don’t see much of a problem with a suitable jumper. Making it a ballistic object with drag and mass would be easy. But a more realistic FDM … Hmmm An accurate FDM would be immensely complex considering all the possible poses a human can achieve. But perhaps something simplistic could be worked up using the arms and legs as control surfaces. My focus right now is not so much getting accurate free fall dynamics, but to get a nice jumper model and then just hack up some sort of dynamics with approximately the right lift/drag ratio for someone is a stable free fall pose. The goal would be to get approximately the right fall rates and timings so that there is training value in solving problems and overcoming various combinations of faults with in a realistic time frame. It's still only a very partial simulation but hopefully a step better than just sitting around in a circle talking through various scenarios. The next step would be to have a canopy that could be configured to have various problems opening up and be able to draw that somehow from the perspective of the sky diver, and perhaps have some appropriate dyanmics for partially tangled or partially inflated chutes? Obviously there's endless variabiltiy and high fidelity in all respects would be crazy to try to achieve, but it would be interesting to take a few small steps forward and see how far we can get. Best regards, Curt. Is lift actually much of a factor in free-fall skydiving? I thought it was mostly just varying drag, in which case the FDM might be simpler than you think. For example, the YASim FDM assigns drag to extended gear elements, which are located at specific points on the aircraft and so act at those points. It might be possible then to hack the YASim FDM about a bit to remove the need to solve for cruise and approach conditions and just use the gear drag bits, which could then be placed and animated to simulate a human body. LeeE -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
leee schrieb: On Saturday 30 May 2009, Curtis Olson wrote: On Sat, May 30, 2009 at 12:02 PM, Vivian Meazza wrote: I don’t see much of a problem with a suitable jumper. Making it a ballistic object with drag and mass would be easy. But a more realistic FDM … Hmmm An accurate FDM would be immensely complex considering all the possible poses a human can achieve. But perhaps something simplistic could be worked up using the arms and legs as control surfaces. My focus right now is not so much getting accurate free fall dynamics, but to get a nice jumper model and then just hack up some sort of dynamics with approximately the right lift/drag ratio for someone is a stable free fall pose. The goal would be to get approximately the right fall rates and timings so that there is training value in solving problems and overcoming various combinations of faults with in a realistic time frame. It's still only a very partial simulation but hopefully a step better than just sitting around in a circle talking through various scenarios. The next step would be to have a canopy that could be configured to have various problems opening up and be able to draw that somehow from the perspective of the sky diver, and perhaps have some appropriate dyanmics for partially tangled or partially inflated chutes? Obviously there's endless variabiltiy and high fidelity in all respects would be crazy to try to achieve, but it would be interesting to take a few small steps forward and see how far we can get. Best regards, Curt. Is lift actually much of a factor in free-fall skydiving? I thought it was mostly just varying drag, in which case the FDM might be simpler than you think. For example, the YASim FDM assigns drag to extended gear elements, which are located at specific points on the aircraft and so act at those points. It might be possible then to hack the YASim FDM about a bit to remove the need to solve for cruise and approach conditions and just use the gear drag bits, which could then be placed and animated to simulate a human body. LeeE Why not start by look for skydiving gps tracks on the net to come up with a model? Cheers, Josef -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
On Sat, 2009-05-30 at 10:24 -0500, Curtis Olson wrote: I know we have a few aircraft that can drop sky divers. The Noratlas was the first one I recall. However, these sky divers immediately pull their chutes and drift down ... and the skydiver/chute model is very simplistic ... optimized to be viewed from the drop plane and optimized to have bunches of these in the sky at one time. Has anyone developed a more detailed model of a sky diver? I'm especially interested in the free fall phase. (My brother is up to his 38th jump now I think.) Many moons ago I played with the paraglider model and added a bit more control. No free-fall, though. http://www.jentronics.com/fgfs/paraglider.tgz Might be a better jumping off point than the current CVS for someone else :) A detailed jumper with articulated arms and legs (even with just a cannon ball FDM to start out with) could be the start of an interesting training tool. My brother speaks of some of the training classes he has gone to where different failure scenarios are presented, but you are sitting (or perhaps lying) on the ground with no real urgency (except some false urgency of the instructor yelling at you.) If some of these failure cases could be cooked into a FlightGear scenario with a free fall sky diver, there could be some good virtual urgency and good training value so students can instinctively learn the right things to do in various scenarios without forgetting key steps or key aspects of the situation. I know we have some nice pilot figures that people include in some of our aircraft. How hard would it be to develop a nicely detailed sky diver model that can be posed in typical free fall positions? Thanks, Curt. -- Curtis Olson: http://baron.flightgear.org/~curt/ -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
On Sat, 2009-05-30 at 12:16 -0500, Curtis Olson wrote: On Sat, May 30, 2009 at 12:02 PM, Vivian Meazza wrote: I don’t see much of a problem with a suitable jumper. Making it a ballistic object with drag and mass would be easy. But a more realistic FDM … Hmmm An accurate FDM would be immensely complex considering all the possible poses a human can achieve. But perhaps something simplistic could be worked up using the arms and legs as control surfaces. My focus right now is not so much getting accurate free fall dynamics, but to get a nice jumper model and then just hack up some sort of dynamics with approximately the right lift/drag ratio for someone is a stable free fall pose. I think a reasonable JSBsim fdm wouldn't be too hard, 2D drag tables for drag in different body positions, separate 2D table drag inputs for main-chute deployed and fouled. Same for backup chute... Cm, Cn, Cl functions for the 'chutes should swamp the body functions... use alpha 0 for standing upright, alpha -90 for head first... Could work... but... How do you control it? What joystick input does what? Before opening the 'chute different body positions affect drag, as well as pitching and yawing forces. Should viewing direction be considered head movement? http://www.dropzone.com/cgi-bin/safety/detail_page.cgi?ID=636 http://www.dropzone.com/cgi-bin/safety/detail_page.cgi?ID=696 Talks about using hip movement to properly steer the 'chute. http://www.dropzone.com/cgi-bin/safety/detail_page.cgi?ID=536 Mentions brakes, toggles, risers. Which button would do what? The goal would be to get approximately the right fall rates and timings so that there is training value in solving problems and overcoming various combinations of faults with in a realistic time frame. It's still only a very partial simulation but hopefully a step better than just sitting around in a circle talking through various scenarios. The next step would be to have a canopy that could be configured to have various problems opening up and be able to draw that somehow from the perspective of the sky diver, and perhaps have some appropriate dyanmics for partially tangled or partially inflated chutes? Obviously there's endless variabiltiy and high fidelity in all respects would be crazy to try to achieve, but it would be interesting to take a few small steps forward and see how far we can get. Best regards, Curt. -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sky dive free fall
On Sat, 30 May 2009 21:42:55 +0200, Josef wrote in message 4a218c3f.3010...@googlemail.com: leee schrieb: On Saturday 30 May 2009, Curtis Olson wrote: On Sat, May 30, 2009 at 12:02 PM, Vivian Meazza wrote: I don’t see much of a problem with a suitable jumper. Making it a ballistic object with drag and mass would be easy. But a more realistic FDM … Hmmm An accurate FDM would be immensely complex considering all the possible poses a human can achieve. But perhaps something simplistic could be worked up using the arms and legs as control surfaces. My focus right now is not so much getting accurate free fall dynamics, but to get a nice jumper model and then just hack up some sort of dynamics with approximately the right lift/drag ratio for someone is a stable free fall pose. The goal would be to get approximately the right fall rates and timings so that there is training value in solving problems and overcoming various combinations of faults with in a realistic time frame. It's still only a very partial simulation but hopefully a step better than just sitting around in a circle talking through various scenarios. The next step would be to have a canopy that could be configured to have various problems opening up and be able to draw that somehow from the perspective of the sky diver, and perhaps have some appropriate dyanmics for partially tangled or partially inflated chutes? Obviously there's endless variabiltiy and high fidelity in all respects would be crazy to try to achieve, but it would be interesting to take a few small steps forward and see how far we can get. Best regards, Curt. Is lift actually much of a factor in free-fall skydiving? I thought it was mostly just varying drag, in which case the FDM might be simpler than you think. For example, the YASim FDM assigns drag to extended gear elements, which are located at specific points on the aircraft and so act at those points. It might be possible then to hack the YASim FDM about a bit to remove the need to solve for cruise and approach conditions and just use the gear drag bits, which could then be placed and animated to simulate a human body. LeeE Why not start by look for skydiving gps tracks on the net to come up with a model? ..we have _some_ sanity here, galskap means insanity... ;o) http://filter.start.no/nettnytt/2977 -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. -- Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, Big Spaceship. http://p.sf.net/sfu/creativitycat-com ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
