[Tutorial] Industrial staircase handrail.

simon le bon

Industrial staircase handrail.

Hi

Have you ever tried to draw the curved part of a handrail?

It is not a big deal but I have spent a couple of hours to find the way to draw these complex curves, and as this can deserve generic purposes I go up my sleeves and give it to you

simonlebon

simon le bon

First some examples grabbed on the net and the link for DC StairCaseBuilder from Howard Leslie a Dynamic Component that can be used to help model Staircases
(not tested but seemingly very interesting)

Industrial staircases

Industrial stairs

Theory
[img:385nz0y5]http://i274.photobucket.com/albums/jj245/Spendauballet/SketchUp/2010-12-03_203137.jpg[/img:385nz0y5]

[img:385nz0y5]http://i274.photobucket.com/albums/jj245/Spendauballet/SketchUp/trappeHaeld1-1.jpg[/img:385nz0y5]

simon

simon le bon

In the process I have used , I have detached a particular case which I call "The simple way"

This particular case fixes two parameters.
1)the horizontal part of the handrail begins by a flat pure quarter of a circle. This way we only have to determine the curve for the remaining quarter.
2)The climbing handrail must axes above the perpendicular axis exiting from the flat quarter of circle I just have talking about. This way the curve we have to draw can bend as a simple arc instead of a "S" curve (and we obtain this way a final shape much better adapted and beautiful)

(the case to avoid:)

I assume you know the need and the use of the following Plugins:
-> Fredo6 BezierSpline (and its 20 sheets PDF !!)
-> Didier Bur Projections Tools
-> Rick Wilson Weld
->Didier Bur Lines to Tubes
I assume also you know how use "Intersect with the model" by entering a group, select all and intersect, in order to recover the path of the intersection..

Basically, my way is to project plane curves on semi cylinders and reversely.
All modifications are made on plane curves.
The understanding of the process, turns around the ability to imagine a flat curve projected in 3D. Please understand and note the necessity to make our original flat curve with endings tangent to the axes..
,..and a remark: it goes better if every part of the construction set is turned as a group!!

[flash=640,480:2tw86mrq]http://www.youtube.com/v/t1FfpfIiRB4[/flash:2tw86mrq]

simon.

simon le bon

Still simple: a double deck handrail:

Cleaning to keep the part of the curve we want is a mess in its middle part. So I prefer put a construction point on each strategic node, delete everything between, and redraw the missing part with line tool (and weld afterward)

*s

simon le bon

Come back to the first exercise, but this time with a complete control on the total curve! This is "The long Way"
The problem is that the curve projected from plane to 3D and from 3D to plane generates problematic aliasing. The tip is to repair the curve on the plane stage of the curve.

*simonlebon

Gaieus

One of those great, epic ones again, Simon, thanks!

Indeed, a seemingly easy thing explained "scientifically"!

simon le bon

Thank you sirs!

Dear Gaieus,
What a pleasure to see the "Watching Man" always on deck;-)
and thanks for the nice compliment

simon

Gaieus

I saw it yesterday already but did not want to comment to make 100% sure you finish the series of posts without interruption!

watkins

Dear Simon,

Is this something you could put in to a .pdf document, perhaps as a follow up to the individual postings. Similarly, for all all you other brilliant tutorials. Thank you for you enthusiasm and generosity.

Kind regards,
Bob

simon le bon

Dear Bob,
I'm touched by your kindness
Sure I can make a PDF. I have discovered the possibility to edit nicely a pdf into Open Office. I'm going to find the time this week.
++ Simon.

jeff hammond

Nice study Simon
I'm on a phone right now but when I get to a computer later tonight, I'll try some things that might make this a lot easier (or at least give a different way of looking at it)

I'm know I can get a smooth & tangent curve in there very quickly but as to it being the proper shape, we'll see

dale

Hey Simon
Thanks as usual. You are such a great contributor.
Cheers

pilou

Cool tut variations!

@unknownuser said:

I have discovered the possibility to edit nicely a pdf into Open Office.

I am interested by this sort of operation
"How to modify an existing PDF"

jeff hammond

so i tried what i was thinking earlier and it does work.. i did this curve in 10 seconds using fredo's BezierSpline.rb (Uniform B-Spline)

railBend.skp

a little different than the example .skp... this one uses shorter extensions and an order 4 b-spline.. (see skp above)

ely862me

No plugin used,just native tools.

simon le bon

@unknownuser said:

so i tried what i was thinking earlier and it does work.. i did this curve in 10 seconds using fredo's BezierSpline.rb (Uniform B-Spline)

10seconds!!!!
I am on phone i need to see that this evening!
Hey Jeff, you've also killed my tut in 10 seconds
simon

jeff hammond

@ely862me said:

No plugin used,just native tools.

lol..

that's how they would probably be built as well.. straight tubes with 90 deg bends on the ends then welded together on site.

jeff hammond

@simon le bon said:

Hi Jeff,
I have Su6 & Su7 and can't read your Su8 skp solution
But I guess you have used something like this way:

oops.. once again i forgot to save as something that everyone can view .. here's a v6 file.

railBend_v6.skp
it's pretty much what you've imagined it to be except i only used 4 points to define the curve. (as you only need 2 points to make a tangent blend to a line)..

it's something i discovered about the uniform b-spline..(in part due to eli's problem solving in a different thread).. here's a post of mine in which i do the same thing to create a tangent (and somewhat editable) complex surface blend using uniform b-splines..

http://forums.sketchucation.com/viewtopic.php?p=267047#p267047

[the video from that thread:]

[flash=660,405:20ue0pp6]http://www.youtube.com/v/8B0RXSW66no?fs=1&hl=en_US&rel=0&color1=0x2b405b&color2=0x6b8ab6&border=1[/flash:20ue0pp6]

simon le bon

Hi Jeff,
I have Su6 & Su7 and can't read your Su8 skp solution
But I guess you have used something like this way:

Hi Eli,
I recognize with great pleasure your special spirit which works to find the simplest way. Your solution is very clever in its simplicity . I agree with Jeff to think that this way has been used usually in construction.

Hi Bob,
I ask myself if we need a pdf right now? Or may be one including Jeff and Eli solutions !?

Hi Pilou,

@unknownuser said:

@unknownuser said:

I have discovered the possibility to edit nicely a pdf into Open Office.

I am interested by this sort of operation
"How to modify an existing PDF"

In fact I haven't found the possibility to "edit" or modify a pdf within Open Office! I have just found that we can edit a complex text with pictures and links(+-?) and record it as a decent pdf. Hum! this is not exactly the same.

++simon.

simon le bon

Dear Jeff,
you show the interest of Uniform B-Spline I have missed until now!!
here page 4 from pdf tutorial relatives to B-Spline and Order parameter:

I know your video I have already watched several times
But your tritubes shows also very well the extension of your technique.

(Re I wanted to relate your realization in wood but the pictures are no more available )

a tip: when the curve is drawn, right clic and edit curve. Then use tab to call Order parameter and change it without leaving the edit mode until you find the good one

++simon