Hi all, I'm trying to make a simple steam engine model in Bryce that will move like the real thing. My model has 4 parts: Piston Housing, Piston Rod, Transfer Arm and Wheel. I am 90% there, but have one problem. I think I am missing a step. Here's what I do: I lay everything out horizontally to make it easier to work with. So it looks a little like this: -- | -- O. The first two dashes (--) are the piston rod, the (|) represents the piston housing, the second dashes (--) are the transfer arm and the O is the wheel. In the model all the edges touch. So far, if I set the origin point on the Transfer Arm to the end, so it touches the circumference of the wheel, and then LINK the Transfer Arm to the wheel (but uncheck rotation) (as it would be mechanically), and TRACK it to the Piston Housing, I can rotate the wheel, and the Transfer Arm will move properly as I rotate the wheel. The tracking makes it point always to the Piston Housing, which is stationary, while the linking allows it to move with the circumfrenece of the wheel. Step one seems to work okay. Next, I set the origin point on the Piston Rod to the end where it touches the Transfer Arm. I LINK the Piston Rod to the Transfer Arm (as it would be in a machine), it will then follow the Transfer Arm, I TRACK it -x to the Piston Housing (which is stationary), and it stays in place. Now, if I rotate the wheel, the transfer arm works properly and the piston rod does move in and out. But it doesn't stay level on the Y axis. It moves up and down, which is unreaslistic. I must be either too literal here, or am missing something. Basically, I need to trap the piston rod so it can only move side-to-side while linked to the Transfer Arm. Any ideas? I have a feeling this can be done easily, and I'm just missing a simple step. Of course, it does work backwards from a real machine (i.e., I must rotate the wheel to make the other parts move, whereas in a machine, I'd move the piston rod side to side and the other parts would move.) and that may be where I am missing the final step. Any ideas would be appreciated. Is there a clever tutorial I am not finding? Thanks for your help!

way doggies we's gettin us a train !!!! don't know what you said : pre-haps a picture i'd help. bikermouse humming: " green acres is the place to be ..." lightning strikes the same place twice - bikermouse recovers.(sort of.)

What you really need is Inverse Kinematics (IK), something that Bryce doesn't have. IK is what Poser uses which allows you to pull on a hand and have the rest of the arm and body follow. I'm not sure if there is a solution to your problem. Is it possible to link the piston arm to yet another object (a null object) which keeps it constrained in the Y direction? Steve S.

Attached Link: http://www.ruinbird.com/pose_1.php

Here are two tutorials. One is for a posable figure in Bryce the other is for a piston. Maybe one of them will help.

http://www.ruinbird.com/piston_1.php

Arleen

Thanks to all for your suggestions and help. Arleen -- Great tutorial site, thanks for the lead! Lots of good information and ideas there. Steve S.-- Thanks for the idea of a null object. I was able to make it work as an animation doing this, but it is so complicated, I can't explain how I did it!

Glad to help. Keep us posted on how it goes. Arleen

ok if you need further help try using a disgram such as the one included - elaborate and add parts (i.e. piston arm.) as you seem to have it under control I won't bother to explain what I have so far other than to say I don't think you'll need a null object to make it work. Good luck on your Industrial Engine. (I was Hoping someone was building a RailRoad Engine.)

Hi All, When I get this thing to work (I did get it to work as an animation, but not as a completely poseable object set--my ultimate goal), do you think it would be interesting to others to post the file so others can see how I got it to work? Or should I make it as a tutorial and post it on my Web site? (Gosh, I never thought I, of all people, would make a tutorial for Bryce!)

1: Why not? 2: Yes and add a link from turorials.

I agree with bikermouse, yes and yes!!

One thing about making it posable. If you use the tutorial on ruinbird's site, you need to know that you CAN make it posable, but NOT animated. I tried with a simple stick figure, and, although the keyframes are correct, the farems inbetween are....screwy. anything that was linked to something else, that moved, became all streched out. I'm not sure how to elaborate on this, but perhaps someone else has come across this??

big_hoovie, I haven't had any problems with "stretching" during animation. Maybe try to make sure you are working in object space. I made a walking manequin once, if you like I could send it to you. (.avi format) if I still have it, I'll have to look.

ya, that'd be great, if you could. how big is it??

Damn, unfortunately I don't have it anymore. I have a skeleton that I've set-up to be posable that's 1 MB zipped I could send you just give me an e-mail address. Everything is parented to the hip, so to move the whole thing you move the hip then pose the limbs, etc. Work with it in object space and it should be fine when animating.

email: big_hoovie@yahoo.com Thanks a lot. now maybe i'll get around to that big animation I've been thinking about for about 3 months

Hi All,

Well, I have written and posted my tutorial on the working steam engine model. I posted the link in the Tutorials Section under Bryce, but here it is also:

http://www.clydesight.com/brsteam

There are actually two models. The instructions show a very simple model, and the one (shown here) is an idea of what can be done based on that model. There are even movies to show the models working! (But you need QuickTime to view them.)

Yeah but can you make it work in bryce 3.1? (without the rotation wheel.) good job! nice clean tutorial.

Ok this had been bugging me for some time now. There had to be a way to do it. I found it, unfortunately you can't do it by just moving one object.....it'd be nice if they could add an option to the link to only keep the x,y,or z distance, then it would have worked that way. I decided to look how an actual locomotive was set-up. OK so here we go The blue circles are the wheels of the train Cylinder 1 in the linkage Cyl 2 is the transfer rod Cyl 3 is the piston rod Cyl 4 is the piston housing Spheres are null objects 1. Link the right wheel to the left wheel with only rotation set. 2. Cyl 1 is linked to left wheel with only distance and offset set. Origin is moved to where the mounting pin would be. 3. Sphere 2 is linked to Cyl 1. This is created because tracking is set to the center of an object not it's origin point. 4. Cyl 2 is tracked to sphere 2 and origin is moved to where Cyl 2 & Cyl 3 would pivot. Linked to sphere 1. 5. Cyl 3 is linked to sphere 1. 6. You may have to make sure sphere 1 is at the same Y coordinate as Cyl 2 & Cyl 3. Sphere 1 is at the x,z coordinates of Cyl 1 (not it's origin handle). Ok to animate we will be moving two objects, left wheel and sphere 1 working in object space. Set your time scrubber to where you want and rotate left wheel by a certain amount of degrees (we'll use 90 degree increments in my example). Now (depending on orientation of model) note the new x or z position of Cyl 1 and then set sphere 1's x or z postion to the same thing (this will give you your lateral movement). Continue doing this until the left wheel comes around full circle. Eureka! you have a working locomotive wheel. Have fun!

In B3.1 you don't have a rotation wheel so if you're using that you will have to set the position of the "arms" manually at 0 90 180 -90 0 as shown in the disgram I posted on 6/4. (unfortionately the transfer arm position at 0 (D) is hidden in the diagram.) this way isn't so hard except that you have to precisely place the arms or they will wobble. parent relationship starts at the outermost wheel and work towards the piston. That way you can figure out a way to make piston work harder in low gear when you add a transmission. . . . But this brings up the question of a transmission. A train engine would have to have at least two gears and a way to make it go in reverse. There does not seem any to do that except inline between the steam piston and the transfer arm. Im not sure that bryce can represent this without cheating, but it's something to think about. - MIT eat your heart out.

Thanks Alderon for the diagram and method, I'll try it out. In my expermients, I have found ways to do some more complex linking still controlled by one object, but as you say, there is a definite problem with wobbling. And some linked objects tend to take a walk, moving in unexpected ways. I agree, we need more control points in Bryce and more flexibility for this type of project. Bikermouse-- Not sure why you are stuck in Bryce 3.1, and I can't help you there, as I no longer have or use it. These constant upgrades are a strain on the wallet, aren't they! As to transmission for reverse, I remember reading about that somewhere. The old steam locos don't have gears at all, just the tie rods that control the wheels. I believe they get them to go in reverse by some sort of action with the steam valves (which in Bryce are not required, of course.) As I understand it, locos use a two stroke piston, where the steam can be sent into either end of the piston case (this also doubles the power of the machine since it is powered when the piston moves forward, and powered when the piston moves backwards), which is different from an auto engine, where the fuel always enters the top of the piston (the bottom is open to the internal crankshaft). To go forward, they ensure that the steam enters one end first that will cause the wheels to rotate one way, and to reverse, they swap the valves, so the steam enters the other side first. At least I THINK that's how they do it. I believe I remember seeing some documentaries on TV about steam enthusiasts who drive the real antiques, and if I recall, sometimes, the things would start in reverse unexpectedly, and they'd have to switch the valves. I'm no expert on that. Mahybe someone in this forum knows more about it. Model trains are easier, you just reverse the current!

The very early steam engines did not have gears as you say. There was an old train I used to play on as a kid. I'm sure that it did have a gearbox on either side with a levers for both brake and gearshift. As I don't have anything to confirm this presently, I won't comment on it further but if I unexpectedly run across something I'll let you know. I ran the reverse problem over in my mind last night and I believe that running into reverse was probably a common problem with early train engines, so much so I'd bet, that it was not unexpected that a train would start in reverse unintentionally. As to bryce 3.1: There is only so much money In my budget available for software.(nuf said.)

Hi Bikermouse, Sorry about your budget holding you back from the more recent Bryce versions. Been there with many programs myself, so I completely understand. I read somewhere that if one started out with Microsoft Word v.1 and ket upgrading through the years, the overall cost would amount to something like $1,000! Guess the software folks found a goldmine in the users. I guess the final analysis about steam engines is that they are fascinating to some of us! Of course, we do this from the comfort of our modern lives. There is a "little" (meaning short run track) steam line in Connecticut that runs during the summer along a scenic route by some river (I forget which one) One thing that became immediately apparent when riding it was the amazing amount of heat that these machines generate, the very loud noise, and the general discomfort (by modern standards) of the steam experience! The engine had a gondola car behind it so those of us who were really into the ride could stay behind the "iron horse" and see it working as we rode along. Needless to say, we were covered in soot and ash by the end of the trip! As I recall, that one too managed to start in reverse for a second, then there was a screetch, a stall, and finally the puff-puff and we rattled forward. Of course, my neighbor's car often starts in reverse too! However, I believe that is called "operator error" ;>)

I went to the old Cliffhouse in San Francisco brfore it burned down for the second or third time. They had on display an old steam powered motorcycle,circa 1909, which they claim was capable of speeds over 90 mph. Talk about loud and hot. that musta been sumpin. Also when I lived in Felton,Ca., there was an old narrow gauge steam engine that took passengers up and down a hill. I never even saw the thing but you coild hear it chugging up the hill, changing gears and making all kinds of train sounds. $1000? really. Every copy of MSWORD ive gotten, came with the os or was otherwise free. But you see my buget is geared to eventually create my own company, and I can't afford to upgrade a product which does not produce 3d output. I have the features I NEED in bryce 3 and until they come out with the features I want, I ain't buying. Besides bryce is low on the list. Lightwave,Carrera,Poserpropack,mike and vicki,tailor, just to mention a few are ahead of bryce.($over 1000 )

Hi Bikermouse, Some of the "hill climber" engines had gears as well as wheels because the incline was so steep, they need rack and pinion gearing to get up the hill. I think the Monagahelia railway (in Pennsylvania) is that type of railroad. It's a short run that goes up a mountain, and of course in Switzerland, this is often used. Also, did you know that many of the modern steam locos and even deisels now a days, carry large quantities of sand on board? Turns out that a steel wheel on a steel track doesn't get a lot of friction and can slip quite a bit. They have special sand nozzels to spray sand under the wheels to give the engines better traction. One would think a locomotive of several thousand pounds weight would have plenty of traction, but when pulling a load considerably heavier, they need even more grip. Also, another trivia tid bit. Deisel locos don't use the deisel engines to power the wheels. The engines run generators, and the wheel power comes from electric motors. There was a self powered passenger car call a "Budd" car used for commuter runs. The deisel engines were on top of the car (thus allowing room for passengers.) I always wondered how they got the power from the deisel to the wheels, until I leanred it is all done electrically. Just some more useless trivia. MACS don't usually come with MSWord bundled, so I was speaking as a MAC user, but the story is similar for many programs. WordPerfect, before they went bankrupt umpteen times and landed in Corel, used to have an interesting policy. They figured out that upgrades were a cash cow, so there was once a directive (I can't prove this, I heard it from a WP techie) that WP would be upgraded every quarter, and the upgrades were to be sold to consumers, not given away. This was in the early 90's I believe (I can't remember for sure...the company I worked for was being squeezed by it because they had bought WP across the board). One of the big issues was that the upgrades were really bug fixes and did not add much to the program. This was again, on the MAC side of things, and for all I know, it could be urban legend. But the company did buy annual upgrade packages from them until they finally said "enough!" and moved to Microsoft Office. I always thought Bryce was a 3-D program. Unless you are referring to a more advanced type of 3-D program, such as Lightwave that allows much more control over shapes and so on. I have Strata 3-D Pro (a MAC product) which supports OBJ and DMF, DXF and other formats. So, when I need a special shape for Bryce, I create it in Strata and then import it into Bryce. I am more comfortable with the Bryce interface than the Strata way of doing things, though Strata is a good program. I just haven't gotten comfortable with it. See ya!