3d solid staircase railing curved at every bends

[shinymathew]

i am trying to make a railing of the staircase using solid modelling. the top bar is 2 1/4" wide and 4 1/2" deep in cross section. by extrusion and substraction i am able to make the straight portions. now with each intersection i have to use a post of 4 1/2" x 4 1/2" in cross section. i want to use a curved piece of te bar instead at each bends. i tried to extract this bend piece from solid annular cylinder. since unable to match the ucs i am not getting the correct profile. any body to help.

[J-LYLE]

Have you tried "UCS>New>OBject" and then select the object your wanting to change. That should get you the same UCS so you can make your new object.

[shinymathew]

thank you j-lyle for the reply. i tried to set the ucs with the object. with that also i am unable to solve the problem. i can send you the cad file if you wish. please let me know. i don't know how to attach a cad file with this message. it is a railing for the staircase. first few steps rise. then take a turn at the landing. then again rise.like that. at each turning the direction of the beam will take a 90 degree in plan view. but the slope is same. now to join two beams a vertical post is placed at the junction. both the beams are joining to the post. if we can join these two beams with a slanting curved piece, the post can be avoided. this kind of members are carved from wood by carpentors. but how this will be made in 3d solid?. a slanting elliptical path for extrusion may be a solution. but while extruding the rectangle which is used for extrusion should not rotate itself. but how to make that elliptical path.hope there are better solutions. any body!
thanks
shiny

[J-LYLE]

What is the slope?

[shinymathew]

the slope is 10"X8" (10" tread and 8" rise for the steps) i am keeping the railing at 3feet height from the step surface through out the length of the railing. when it turns 90 degree in plan, in order to maintain the same height of 3feet in the next part of the stair an off set of 3.2" is required. this may be neglected for the trials.
i am using autocad 2004.
thanks
shiny

[J-LYLE]

Ok what ya need to do is get two lisp from the forum here to help you out one is "Helsurf" and the other is "m2s". First you need to use "helsurf" to extrude your profile then "m2s" to change it from a mesh to a solid. I tried to attach a pic here but i did something wrong not sure what and i couldnt get it. If you have any problem re here and ill send you an emiail with the step by step and the dwg of it.

Oh when you use "helsurf you have to make sure that your axis for revolotion starts at 0,0 and says on the x axis for it to work then you can move it and rotate it after it is created.

I figured that one revolition at the pitch you need is 38.4" in height. then you only need 1/4 of that for your elbow. Let me know how it goes

[J-LYLE]

Look under file manger (top right of screen) here for "railing4.pdf" youll see a pic of it

[shinymathew]

jlyle!
thank you verymuch for the efforts you have taken. this seems to be the correct method. i have seen the railing4.pdf. i want to see the top view and side views also. please send me the cad file. also the step by step routine of using the lisp files. i am not very comfortable with lisp. how to laod and use it. i got the m2s.lsp file. for helsurf i pasted the listing from the forum in note pad and saved as helsurf.lsp. is it ok. is there any
graphic method other than lisp program. if we have a program like m2s to convert the volume enclosed in a bounded surface to solid models it will help us in a number of problems other than what we are dealing currently. hope m2s.lsp will do that. will it give the mass properties of the converted solids. is there a way to make an elliptical path and to extrude a rectangle along it after setting a ucs. or by subtracting from a pipe element with boxes after finding a common ucs.
is there any lisp program or graphical method to make rectangular thread on a bolt. these are just some ideas i have in mind. but i am practically not able to do! may be my limitations in mathematics. or may be my lack of cad skills and lisp skills.
thank you verymuch for the help. i am waiting to practice it.
regards
shiny

[J-LYLE]

Yes you can copy the code into notepad for the lisp and save it as "_ _ _.lsp but the main thing is that the extension is .lsp then you can either go to Tools>load application or simply type in "appload" on the command line, then go to the location where you saved the lsp and load it. As far as useing the lisp or any lisp somewhere near the top most of the time you will see c:m2s or something what ever is after the c: is what you will use as the command to start the lisp. Then most will prompt you on the command line with what info you need to supply for the lisp. ex.. length? height? number? and so on.

I will create a short step by step of what i did to create the elbow with the lisp but it might be a few hours b4 i can get to it.

The "m2s" lisp im not to familar with myself ive only used it a couple of times so im not real sure of its capabilities, but its been a huge help form me, without it i dont think i could have created pieces like the elbow in question. Ive never tested to see if you can check the mass prop of the "m2s" solid but i wouldn't see why you couldnt.

As far as creating a elliptical path. The path I created here for your elbow is actualy a helix. Their is another lisp here called Helix that creates a spring like extrudable line, but if the object your extruding is not round the it will turn as goes around. Im sure if you type in "helix" in the search section of this site then you will get a lot more in-depth info.

I will email you a cad file with the elbow on it, then latter i will try to post here a step by step on the elbow.

[shinymathew]

j-lyle,
thank you very much. received the files. cad aswell as wmv files. i have got the three .lsp files. helix, helsurf and m2s. all are working properly. i loaded them as (load"helsurf") ...now i will try based on the files you have provided. i will study how to give the input for making the mesh. the other program m2s is simple. there we have to select the already made mesh only. it will convert the mesh to a solid. it will give the massprop also. i copied them into the auto cad directory where acad.exe is kept.
thank you very much once again. i will come back once i complete my trials.
regards
shiny