Cineversity

Hi,
stairs are a little bit tricky. In my case, as an architect, I have to modell a curved concrete stair. Important is that the view from the bottom is organic. Like in the attached picture. Damn I cannot upload a picture. Here is a Link:
https://www.google.com/imgres?imgurl=https://www.treppenbau-kubasch.de/img/Geschosstreppen/MD002846_gross.jpg&imgrefurl=https://www.treppenbau-kubasch.de/geschoss.html&docid=0JwArF-4Oj20tM&tbnid=h-BgEr9dxiifhM:&vet=10ahUKEwjBlpTUsJTnAhVMUhoKHQ_jBWQQMwiMASgPMA8..i&w=600&h=800&bih=1297&biw=2560&q=viertel gewendelte Treppe beton&ved=0ahUKEwjBlpTUsJTnAhVMUhoKHQ_jBWQQMwiMASgPMA8&iact=mrc&uact=8

I have Spline from autocad with every unique step.

But I have no idea how to put them together in order to have a smooth stair view from the bottom.
Can someone help me?

Greets

Hi info,

Images can’t exceed the 600x800 size. Non-image files need to be “zipped” and limited in size (~4MB)

As an architect, you will know that a “Viertel-Gewendelte-Treppe” is based on the technique called “Verziehen”.
https://images.app.goo.gl/BNyqvwmKMiynTzyh7

I assume you wrote from Germany, as the Link (didn’t work, I googled the image) had the “quarter newelled stair” in it.

This technique is based on a second path along the inner side of the staircase, whereby the distance is progressively smaller then wider again until it fits (end and start) the typically staircase size again. In Germany, this is based on the Step size length and expressed in two hight plus depth, as you undoubtedly know, (but I write in a forum, so I have to be more detailed), shown in a side view drawing for the concrete builder, here especially with the (often) curved downside of the staircase. This “sculpture” like construct is not something that can be created with a simple function in Cinema 4D. It is based on manual modeling.

The 3D version is usually given with any Staircase created in Archicad or Allplan by default. I assume that you have the 2D Spline “drawing” only. If I had this Spline, I could perhaps give you some pointers. As I don’t know what you have, I can’t be sure.

Except for a week in the early ‘80s, I have never used Autocad anymore, and I stayed for all Architectural projects in Nemetschek products (Allplan, Archicad, and Cinema 4D). Though, I haven’t used any CAD in years. So, I assume the Autocad version, if set up in 3D, can produce this, of course, but obviously, this has been not supplied to you.

I can send you an upload link for the Spline file, just let me know. I need the hight of the single stair then as well. (P.S.: Our PM system gave me grief in the attempt to send you an upload link. For security reasons, I only download from: DropBox, Amazon, Apple, Adobe or Google)

Cheers

Example:
Based on a “spline-drawing”

The project file and screen capture.
https://www.amazon.com/clouddrive/share/B5N7Dz7ZADQnrAOBeCkHZnObkrUbZ6CK0eRNVgk46zJ

The more data (points) are given, the more detailed the mesh will be. Above is more a sketch to give an impression. File 04 has some additional care.
https://www.amazon.com/clouddrive/share/jOj4yvVry7GxD9mK9Zlp2MShcUdTRvdxbs4APNZENrE
Screenshot
https://www.amazon.com/clouddrive/share/39Uw0jmctaihpj0qhPkDRzqCMZsYcmN6JCauvSPP4Md

Hi Dr. Sassi,
wow this is more than I would have expected. Thank you very much for this detailed answer and the very handy screen capture.

Yes you are right. I’m an architect from germany and I went somentimes in trouble when I try to modell organic stair shapes. Although I modell all my designs in 3d my drawing workflow is quite oldschool. I know that archicad has some functions (stair module) that would fit all my needs when it comes to stair modelling but until now I work in 2d only.

2d polygons to cinema.

OK. Your way was also my „plan“ to solve my Problem. But I hoped that there is a tricky solution with splines in combination with lofts or sweeps objects.
That is indeed a very „manual“ technique. But this works for me fine.

The thing is, that a „viertel-gewendelte-treppe“ or better all concrete stairs has a defined width of the „steg“ under the steps. For example 14cm. And I love to work and model precisely. It makes me crazy to position the second path under the steps approximately. 😊

Thx again!!!! You helped me alot
Greets from Cologne
Robin

Hi Robin,

Yes, there are undoubtedly many ways to do it, including your ideas with Extrude. I would say it is a mix, based on how the given Spline is, the expected quality of the mesh, and the time spend. Since I had no spline, I drew one, and with each stair-element being separate, I could select all and place a “num*17” into the P.Y field. Which means, num standing for selected number (like an ID number) that the steps are moved sequentially up.
With snapping on, I created the lower path using the “inner” step vertices of each step. After all, was done, I moved the new Spline just down to get my wanted dimension of the staircase.

I tried to Extrude [top], Loft [bottom], and Boole [both] from there, but the resulting mesh was not as clean as wanted, while time was invested, of course. The example in post #2 took only a short amount of time longer (minutes) and produced a very clean mesh. With this mesh, I was able to explore other steps as well. File 04 has some extra polygons in it from that exploration; certainly something I would not need (half of the extra polygons).

If I had an idea what kind of spline/polygons you have, even an image or sketch, I could explore this a little bit more. The example above is based on the way I created such things in concrete. Using Wood-boards, applying plaster to get a beautiful surface under the staircase, etc. Hence why I tried to come close to the way the “Schalung” is created. I mention all of these details, as the visualization/modeling should contain the way it will be in reality. I assume that some artists reading along have never worked during their summers on a construction site.

Thanks for the extra info. I always loved to be in Cologne. Since I grew up relatively close to it, and during my first study, we often visited studios/ ateliers of friends, and museums, of course.

I will take a look at other options and post here if something of value (time v. quality) shows up.

Greetings from L.A., CA (9-hours behind Köln)

Hi Dr,

thx again for your answer. How small the world is. But regarding your Surname I expected you have a german or austrian background. 😊

I attached my base source (I modelled the stair following you explanations). Not bad but I messed up a little bit with some impossible geometries but nothing what is not solvable.
I tried your approach with the boolean a few years ago. But even today Cinema (and I love Cinema) is a shitty program when it comes to boolean operations. Visually booleans seems to be good but in the end when it comes to texturing I always see that the geometry is crap. For example if you model a saddle roof and boole some skylights in there the following texturing of tiles is completely unacceptable. But that is another issue.

I would be very thankful if you have in idea how to optimize those technique in order to get an better and more precise result.

One last question:
In my file there are two, I called them, leadinglines which defines the height oft he „Steg“ .

Is it possible to make them more evenly? In this case „2-seitig-viertel-gewendelte Treppe“ I manualy move the points visualy in the sence of proportion. Thats OK but, as I said, I hate this.

By the way:
I studied your old modeling Tutorials on Cineversity. Even though they are outdated, they are stil awesome and very very useful. I hate Cinemas boolean technology. It was quite fascinating, how you modlled screws and other stuff with the poly technique.

Maybe this stair „problem“ is worth another tutorial!? Because organic stairs are very hard to model precisly.

Cheers to LA. you lucky man 😊 In Cologne we have -2 degree. Very ugly wheater!
Robin

Hi Robin,

I can’t see an attachment. Sadly the Private Message does not work when I try to send you the link
I got the file-Thank you!

I will have a look at it.

Thanks for the interest in my “old” stuff! I have had slowed down with tutorials to work on my movie, but that is not going as fast as I like. We will see. So far, I have not found anything that is significantly faster than what I did above, and yes, the Boole procedure needs good content, to begin with, so why not invest the time directly. My time advantage of Boole vs. Manual is only a few minutes paid with the loss of elegancy of the mesh. So, no, go here.

L.A., yes, the Sun is shining but its cold for here, I’m domesticated after 15 years of Southern California’s heat, anything below 20ºC is not acceptable anymore

I will delete the link when I get the file, perhaps copy it for the time being.

Cheers

Robin,

Thanks for the file.

I would go with the inside point of the spline to produce the Inside and outside leading spline. To create the thickness (Laufplattendicke), you can then move that spline down. Which might not give the right distance in each case.

To get a handle on that, you can place a circle with the desired measurement on the step points. (Use snapping for that).
This gives you an indicator of the thickness needed. From my point of view, this is a minimal request. With this in mind, the produced line can create a slightly larger local distances to get a pleasing shape, after all, this is also about aesthetics, not just engineering.

I have done this by copying the leading-splines, set the corner points to Hard-Interpolation, and reduced the number of points between corners to the minimum needed. (The lower the point number, the more power to determine the spline has)You might get this from Illustrator works, perhaps already into your muscle memory.

The project file and scree-capture
https://www.amazon.com/clouddrive/share/GlbLemWzy97aPUuG3uRdDNhYjgCWcZeY8nuQrOKmROm

My best wishes

P.S.: I took your file and went one time completely though it.

Screen capture and project file 02, as well as 04.
https://www.amazon.com/clouddrive/share/RSsUdwaPmzLji6DTFEomG0S6FfZrxwXLKmJnF0qe8sh

File 02 is more the raw model, and the 04 has some more ideas in it.

The screen capture is compressed to one minute; as you know, the task, I hope the steps shown will give an idea. Again, there are many ways to do this. For example, the Leading lines can be used to draw Spline> Add> Cross Sections on it, which creates a beautiful collection of short splines that work nicely with the Loft object. An excellent base to start from.

My best wishes for your project.