topic Re: Half height riser in Modeling

Half height riser

Anonymous — Wed, 24 May 2023 17:23:59 GMT

i have only just started to play around with AC22 & i need to model a staircase with a half open riser or half height riser.
i have tried the morph & save as library part, but could not manage to get the custom riser to sit at the correct heights when placed.
is there an easy way that i am missing?
I have attached a screen shot of the sort of thing i need.

Re: Half height riser

Barry Kelly — Thu, 08 Mar 2018 00:33:39 GMT

Rogerdodge wrote:
i have only just started to play around with AC22

I think you might mean AC21 - otherwise you are posting in the wrong forum.

I haven't done it myself but my understanding is you create the stair with a regular riser an then select one and convert to a morph.
Edit it as you want it to appear (in the correct position) and than save as a custom riser.
Now you can use it in the stair.

Barry.

Re: Half height riser

Anonymous — Thu, 08 Mar 2018 20:31:49 GMT

Hi Barry, yes i did mean 21.
I tried the custom riser, but having problems getting it to the correct position, just wondering if there was an easier way.
Thanks

Re: Half height riser

Barry Kelly — Fri, 09 Mar 2018 01:19:16 GMT

I just tried it following these steps (no pun intended ) and it worked fine.

https://helpcenter.graphisoft.com/guides/archicad-21/archicad-21-reference-guide/elements-of-the-virtual-building/construction-elements/stairs/custom-sub-elements-for-stairs-and-railings/

After you modify the morph and save as a riser object, you will be asked to define the position (I was doing this in 3D).
You need to select the top centre of the riser and then a point along its length to set the centre point and rotation of the riser.

Barry.

Re: Half height riser

Anonymous — Fri, 09 Mar 2018 04:58:19 GMT

Ok, I have now managed to almost get where I need to be with your help Barry.
But I also need a tread projection of 15mm min.
So I start with the tread projecting, convert the bottom riser to a morph & save as library part, then change all the remaining risers to the custom part, but I cannot get them to be set back from the tread the 15mm
I have put a morph line on the tread to set the location & tried this several times but they will not project back from the start of the tread.

Re: Half height riser

Barry Kelly — Fri, 09 Mar 2018 05:26:20 GMT

I would say it is a bug.
I would expect the custom riser to respond to the nosing (riser) offset the same as a standard riser, but it doesn't.
Seems you have to move the morph back the required distance and make sure you use the front bottom centre of the tread as the origin.

Barry.

Re: Half height riser

Anonymous — Fri, 09 Mar 2018 05:56:18 GMT

I cannot get the rest of the risers to set back no matter where i put the morpth

Re: Half height riser

Barry Kelly — Fri, 09 Mar 2018 06:06:47 GMT

It is not so much where you put the morph when you save it - although setting it back makes picking the front offset distance easier.
The important part is setting the origin point 20mm in front of the morph - or what ever distance you want the setback because it is not adjustable afterwards.

So for a flush riser you would pick the top centre of the riser as the origin.
For a set back riser you pick the same point but 20mm in front of the riser.
Then select the entire stair and change the risers to your custom object.

Barry.

Re: Half height riser

Anonymous — Fri, 09 Mar 2018 08:45:26 GMT

Did it, thanks Barry
I had to use a 3D morph line projecting from the top middle of the riser out to the front of the stair to set the origin point accurately.

Re: Half height riser

Barry Kelly — Fri, 09 Mar 2018 08:57:41 GMT

Excellent.
If you have the snap points active you shouldn't need the extra morph lines as you can set the snap points to 'half' to get the centre of the front edge of the tread.

Barry.

Re: Half height riser

Anonymous — Fri, 09 Mar 2018 19:52:21 GMT

Got that Barry, but i couldn't get the origin point 20mm forward of the tread

Re: Half height riser

Barry Kelly — Mon, 12 Mar 2018 01:43:56 GMT

Rogerdodge wrote:
Got that Barry, but i couldn't get the origin point 20mm forward of the tread

Push the morph riser back 20mm and then use the front of the tread as the origin.
Then you don't have to try to find a point 20mm out in space.

Barry.

Re: Half height riser

Anonymous — Mon, 12 Mar 2018 07:11:03 GMT

Got it, I had been setting the riser back, but i hadn't been picking the correct spot for the origin, takes a bit of practice & expert guidance
Thanks for your help Barry

Re: Half height riser

Daniel Kovacs — Wed, 28 Mar 2018 16:29:18 GMT

Barry wrote:
I would say it is a bug.
I would expect the custom riser to respond to the nosing (riser) offset the same as a standard riser, but it doesn't.
Seems you have to move the morph back the required distance and make sure you use the front bottom centre of the tread as the origin.

Barry.

Hey Barry,

No, this isn't a bug, it was designed to work like this. In case of GDL coded risers/treads, we can calculate with the riser offset setting easily. But in case you are saving your own riser/tread, it would raise a lot of questions: where to position the front of the riser to begin with, where to position the nose/edge of the tread, etc.. It would also be confusing for everyone, if you saved the riser and the tread as one piece (eg. a single riser) with the position you wanted, and it would still be pushed back 15 mm (because that's the default riser offset), whilst you don't even have treads.

To circumvent all this fuss, the geometry you save will always be positioned according to where the baseline runs (that's basically what you select when you save the riser, a 3D extension of the baseline).

I hope I could explain why it works like this. Have fun!

Regards,

Re: Half height riser

Barry Kelly — Thu, 29 Mar 2018 02:37:01 GMT

Thanks for the reply Daniel.
It is a little incosistent though.
The custom riser responds to the tread thickness.
If I change the thickness of the tread the riser will move up or down.
So why not if I change the nosing offset?

Plus if it is a standard riser I can alter the nosing for each individual tread and the riser will adjust accordingly.
If I have a custom riser I will need a different custom object for each different nosing distance.
Not that this would ever happen of course.

A custom riser is just an object like the standard risers so I am not sure why its position can't be changed just like a standard riser object.
The geometry is not being changed, just the position it is being placed.

Barry.