How do I animate con rods?

[ppeacock]

Howdy folks, I will try this post again, it didnt seem to post last time. I am working on my first steam (very simple) loco its just a little 0-4-0 using TSM. I have the loco up and running and just need to do some finnishing touches. My question is probably very simple for most of you people I suspect but we all have to start somewhere. Q.:- How do I get the connecting rod accross the wheels to animate and follow the rotation of the wheels? I feel if I can just do this then I can move on and experiment further maybe getting the valve gear rods to work too. I have done a search on the matter and the only two answers left me no wiser I'm afraid. Also the help files in TS Modeller are no help at all. I suspect the answer may be something to do with setting the part parent and then the axis!!

[ppeacock]

OOpppsss!! sorry,,, forgot to say thank to all in anticipation

Regards P

[altitude10200]

I had to figure it out on my own pretty much but once you do it the first time it gets easy.
1. make sure you have the number of frames set to what you want (usually 8) this is in the project preferences

2. Find the radius of the rotation of the con rod (where the rod it attached to the wheel)

3. I select a disk and set the radius to that of the con rod attach point, then place the center of the disk over the center of the wheel.

4. Make sure that you reset your axis and center it to part. (If the animation does weird things when you try it in TSM this is usually what causes it)

5. Click on animate

6. set your first frame to where the part is when you first click animate (if it is in the right spot, this way the part won't jump when the locomotive starts moving)

7. move the around the disk 45 degrees, the lines on the disk help to make sure it is pretty close to 45 degrees, and rotate the part so that it stays horizontal.

8. keep doing this all the way around until you get to the last frame, when you get to the last frame, go back to the first frame and change the frame number to 8 or your last frame. (this insures that your animation will have a smooth cycle start and finish.

that is about all there is to it, the other gear is basicly the same process as above. There is one piece of the gear that doesn't need to be animated, it is the flange that the small rod that is part of the reverser connects to it is supposed to rotate with the wheel so I just make it a part of the wheel and it rotates just fine.

Hope this helps!

Brandon

[ppeacock]

Many, many thanks Brandon. Your instruction makes clear sense. Even to an old duffer like me. I will give that a go tonight... Later I will try to post a screen shot of my first little loco. Up to now I have not been able to paste into this forum message box.

Regards PP

[smyers]

ppeacock:

I follow a similar scenario. I use 16 frames for valve gear, tho, I find it a little smoother in operation. Set the number of frames in project properties (16+1 = 17). Also, I'll make a "crankpin" part and join it to the main driver wheels part. In the case of your 0-4-0, it would be "wheels2", I think. That way, I can lay the connecting rod end right over the crankpin, frame by frame, using the move tool. Be sure to "Set Motion" and "Set Rotation" when you're satisfied with the rod position. Then advance to the next frame, position the rod, set motion and rotation, and so on till finished. If it looks good when dragging slider, try creating a TS object and run it in the sim.

To do the other side, I'll copy and paste the selected part, noting the exact "x" coordinate. Move the new part to the exact but opposite "-x" coordinate. Go to part properties and rename the part "Rod02". Then click Aninmation in part properties. A window will open listing the frame numbers and the x, y, and z coordinates for motion and rotation. Highlight the first line, click Edit, find the "x" value, place a "-" (negative sign) before each x value, save and repeat for every x value. The copied rod should now rotate in the correct vertical plane. This system works really well unless you want to quarter the drivers. Then you may have to animate the left side seperatly. A lot of work for a marginal gain, I think, unless you're fastidious about details.

The other rods will require the move and rotate tools to position
correctly for each frame, but it's not nearly as difficult as it may seem, just a bit tedious. You can also save and re-use your motion and rotation files for another project. They may not fit exactly, but may start you off on the right foot.

I recommend visiting this site, http://www.tcsn.net/charlied/, to more fully understand steam locomotive valve gear operation. There you can download (free) small exes to your pc. When run, they'll show the various valve gear types in animation, using vector graphics.

Hope We're Helping!
Steven D. Myers

[np2156]

I followed a similar process as far as using "crankpins" attached to the wheels to help with aligning the rods at the various keyframe points, and also using a 16-step animation, but there were a couple of things I did differently.

First of all, in addition to the crankpins, I also split the ends off of the crankpins and attached them to the rods - these really helped with the alignment. The crankpins should have as many sides as there are steps in your animation so that as the wheels rotate, the faces of the pins will still align. Delete them when you're done.

Also, after I had made the right side rods and duplicated them on the left side, I joined both sides together to animate them. When the basic animation was done, I split them apart again (I numbered right side odd, left side even). Then I edited the left side animation for each rod so that what had been steps 13-16 became steps 1-4, and steps 1-12 became 5-16. I also had to change step 0 to match the new step 16. That gave me quartered rods without having to do the whole animation process over again. When you're viewing the model in TSM you'll still see the left side rods in the same position as the right, but if you flip through the animation frames, and more importantly when you run it in MSTS, you'll see the rods in their proper quartered position. Hope this helps!

[ppeacock]

Many Many thanks to you people one and all! After approx 4 1/2 hrs I managed to get one side working. The guide disk suggested by Altitude 10200 was a brilliant idea. I came to grief when trying to get the other side working. Every time I released the loco brake the rod dissapeared!!!! Also has anyone got an explanation on the rod that I gat working would stop rotating as I applied about 45% of loco brake? (I am using Eng. file from F/Scot. If I applied sand the rod would animate again.

NEway I carried on trying to get the other side working and finished up with NONE working. At that point I decided it was coffee time and a couple of headache pills.

Just a mention,, I cant get the animation slider to move! any offers on that one?

Kind regards and if any of you are Brits, God save our Queen!

[smyers]

np2156:

Thanks for the quartering tip! I did try the re-numbering trick,
but I think I missed the 0 to 16 part. The rods would skip back a frame in MSTS, I thought it might not be possible. I have a modern ten-wheeler with 69" drivers roughed out where it is possible to see the opposite rocking link and crossheads under the boiler if you look hard enough. Quartered drivers would look better, especially if it's fairly easy.

Many Thanks;
Steven D. Myers

[ppeacock]

Steven!!!! A TEN WHEELER !!! I have just come out in a cold sweat at the thought of animating that lot. NEway, I have again managed to get one side working perfect and will try Steven's method of copying and pasting the other side tomorrow. For now I need my ugly sleep. zzzzZZZZZZZ

Many thanks again you people for taking the time to help out an old Duffer. I do have nearly 60 candles on the cake so I think I have a great excuse!

Cheers again PP

PS the animation slider does work! silly me.

[ppeacock]

Many thanks again to Steven and the guy's, I copied and pasted then made negative all the X entries and it worked perfectly!!!
Now for the piston rods!
Regards PP

[smyers]

ppeacock;

Glad to hear you're enjoying success, over there. The important thing is to keep at it, and before you know it, you'll be turning out your own BigBoy, Garrett or what have you!

Steven D. Myers

[black5]

Hi ppeacok..
Your rod might not work at 45% braking simply because the wheels are locked....the fact that sanding increases grip which gets the wheels to rotate again....!!?? Just a wild guess...but plausible.
Georges from London

[ppeacock]

Howdy again guys (and Gals if there are any here abouts) Got my rods all up and running perfect! many thanks for the help.
My next main problem that I am unable to solve is how to make the little round windows in the section (bulkhead) I created at the front of the cab. Any tutorial would be most appreciated. Its not that I dont try first before I ask for help but in the end I am not too proud to ask for help.

Wish I could get a screen shot paste up here, somebody might just fancy this little loco. Has anybody got any idea's why I cant paste in this message box? I know how to grab a screen shot and manipulate to size and ssave as JPEG in PSP but they just will not show when I try to paste.

George from Landon,, Many thanks for your post. When the rods stop turning with the brake I could have understood it if the wheels were locked but they arnt!! the wheels are still running it's just the rods that lock under braking. I intend to play about with the "eng" file later see if I can fix it. (obviously with a back up) I have noticed that some of the Loco's my son has downloaded from here do the same!

Regards PP

[ppeacock]

Sorry again, I just reworded my search on transparent windows and have downloaded a tutorial from Brian that I am going to have a go at tonight!

God loves a tryer! they say.

Toot Toot!!!