Posts by MDIvey

    Sitting looking at lines of code for an hour this morning I've come to the conclusion that I don't understand this enough for it to be worth me wasting even another week on this so I've reluctantly had to admit defeat and give up. Perhaps Alex will succeed in getting his Mk9 Spitfire done so we can enjoy flying that in AF2 but I'm afraid my models wont be making it into AF2 skies. Sorry.


    I spent some more time on this yesterday but it still doesn't work... I really can't see what the problem is. I took the rigid body graphics out for the lower leg and wheel, but had to leave their dynamic sections in or the TMD crashed and the Cessna was loaded. The axis on the joint with fuselage.... can I clarify should be the hinging axis, I.e running roughly front to back... or should it be along the UC leg axis which is sideways in plan view but twisted backward 30deg? In either case to calculate the x0 value I need to get a vector from my spreadsheet using two points along it? R0 can be the pivot given in my spreadsheet or that point on the corner of the door that I've been using? One final query... should the hydraulic cylinder be bent back at 30deg so that it's acting directly inline with the retraction?

    This might give me some things I can try. I'm going to focus on getting this done this week... or at least making some significant progress. If I'm unable well I think it will be quitting time. Whatever happens I do appreciate the help you guys have given me.


    This is the code of the joint. R0 I've put in as the xyz co ordinates of the point on the Gear door shown above

    1. <[multibody_joint][JointLeftGearFuselage][]
    2. <[string8][Body0][Fuselage]>
    3. <[string8][Body1][LeftGear]>
    4. <[tmvector3d][X0][ 1.0 0.0 0.0 ]>
    5. <[tmvector3d][R0][0.029 0.844 -0.853 ]>
    6. <[float64][Kp][0.0]>
    7. <[float64][Kd][0.0]>
    8. <[uint32][Type][0]>
    9. >

    As you say...

    Regarding X0:

    Set a rotation around Z by 30deg and a y rotation by 5 degrees. No additional 90° rotation since the gear is defined in the down state.

    1. <[tmvector3d][X0][ 1.0 0.087266 0.523599 ]>

    Is that correct? (radians)


    I've re-jigged the model so that using this pivot point on the door (which is now attached to the upper gear)….

    These angles...

    The Gear should tuck neatly away.

    I cant work out how to translate this into what to put into the Matrix Generator... is this right?

    Ive attached the latest version of the TMD, TGI exporterTM Log and Aircraft converter log. Maybe you can make some sense of why its not working?


    Another day spent stabbing in the dark and getting nowhere. I don't think I can take much more of this. I know you don't want me to give up and I don't really want to myself but there will come a point where I have to for the sake of my sanity.... my mind is getting like this:)


    thanks for suggestions guys... I have some idea of what to try next.

    Steve.... I'm still a bit perplexed by what that X0 value is meant to be. What I actually did was take points from the actual hinging axis for the upper part of the undercarriage and use that vector calculator I made to get the values.... which does point forward more than other directions. I'm getting the impression from what you said that the vector maybe needs to be along the line the undercarriage takes when it's up?

    I think ill try and get the gear to retract just through 90deg first and then if that works hopefully you guys can help me work out how to deal with that compound angle. It's very tricky geometrically, but I understand why it was done.... because of the wing box spar.

    Let you know how it goes.


    The Graphic parts do seem to be rigid body graphics rather than say bending body graphics. Comparing different TMD files I notice with bending body graphics an additional code section is needed to specify the rotation axis and pivot and where the angle comes from... where as rigid body graphics don't seem to need this... perhaps because you've already specified that in the dynamics section. I wont mess with this until I've got some feedback from you guys so that I don't waste time going in the wrong direction... but I'm obviously looking for the simplest way of doing this.


    Do you have the same pivot point on the lower side of the gear and the upper side of the gear?

    Sylvain ....In answer to your question I'm not sure I have. I took the inertia box size of each object from the information displayed top right in AC3D and the R0 value was the object centre displayed in the object information box. Is that incorrect? Wouldn't be surprised😀


    I think I copied the code from the Baron and so I guess the B0 values was omitted. I read somewhere that it can be omitted if the standard matrix is required. You may have a point here Kai. I may have to work out the angles involved and put them into Jans matrix generator. I guess I'd been thinking that as I'd put the axis vector in the joint it wasn't needed. Certainly worth looking further.

    The parts do return to correct position. I will post whole TMD later when I get time so you can see if the graphic bits are wrong.


    Here is code for left Gear, rigid body section

    What I thought I'd done and what I've actually done could be very different. I think I've made the pivot an angled axis on the join with the fuselage. The lower gear is joined to the upper and has a linear translation axis that follows the centre of the upper leg. The Hydraulic cylinder should be pulling the gear upward via an offset pivot on the upper leg and the oleo should be placed so as to stop the leg collapsing on itself. The gear looks like below. Ignore the hydraulic cylinder visualization as I changed this to a vertical orientation since you don't see it... adding the parts just help me find the R0 and R1 point values


    I have adopted that approach... just been working on the left gear. Figure if I can get that to work I should be able to apply that to the right. Had a bit of time this morning so I tried tinkering with it, but it still doesn't work as I expected. Hey Ho :) I've run out of ideas for now.


    Matt me old mucker, don't give up, your models look fantastic and are much needed.

    Reach out to our Jedi Master Obi Jan Kenobi. The undercarriage is the hardest bit, I don't get it myself but I'm willing to have a look if Master Obi Jan is busy


    I did ask for Jan for help with this a couple of weeks ago Steve and didn't even get a reply. I understand Jan's busy, but I cant waste endless hours without purpose stabbing in the dark. I'm not totally thick and have worked out a lot of stuff for myself with little or no help and I'm pretty certain If I was helped over the hurdle of the UC then I wouldn't need to keep asking the same questions again. However it does seem Jan is the only one who really knows what they're doing and if he isn't available then there doesn't seem much point going on with this.


    FYI I'm suspending work on developing these projects for Aerofly FS2. Disappointing I know and I'm sorry believe me... the models look great and AF2 is a great SIM. I've made much progress with doing the TMD files for the Spitfire to the point where the control surfaces and Props are working but the Undercarriage has proved to be a brick wall I cant get over though I've spent many hour trying. The incomplete nature of SDK documentation and lack of knowledgeable help available makes this a battle I don't think I can win. I may continue working on them with a view putting them in another SIM like XP11, but as far AF2 is concerned its over at least for now.


    I think that would be ok as far as anything I post here but always with Caveat that you use at own risk. Bare in mind though Nick this is for Aircraft specific development... might be better to have a separate thread for Scenery specific development stuff... otherwise could get confusing possibly?



    The Spit has split flaps... a small one on the straight stub of the Wing and a larger one outboard on the main dihedral part of the wing. I managed to get this to work along with that insane 85deg angle without resorting to the complex jointing that was needed on the Corsair. FYI here is the code. It works fine and I cant see any problem with it but Jan can verify.

    KR Matt

    Dynamics Section (doesn't include references to Flaps in airfoils)

    The figure 1.35 above was what seemed to get the desired angle of extention… was 1.0. Arrived at 1.35 by trial and error but would be nice to understand why:)

    Graphics Section

    KR Matt