How to change the slope direction of a slab?

[Wolfgang_Schau]

I draw a garage slab and the slope always goes from right to left, instead of front to back. How can I change the slope direction for a slab like a balcony, garage, etc.?

[R_Tweed · Accepted solution]

 If you right click on tool and apply tool properties to line work, you can pick your pivot point location. Using a polyline as a base for the outline works well for this method.  Another option is to create a flat slab and use mass elements to create the slope.  I've attached a dwg that has three methods as options.

[Wolfgang_Schau · Accepted solution]

No matter where I drag the pivot point, the slab always tilts right to left instead of front to back. For the garage I deleted the slab and start drawing it from a different corner, now it slopes from front to back, but I don't get why.

I used your drawings and experienced the same problem; the second drawing always swivels from right to left. Could be something wrong with my AutoCAD Architecture 2024 installation? 

I have attached my drawing. the problem is the north balcony slabs in the B-slab layer.

Best regrads

Wolfgang

[David_W_Koch · Accepted solution]

The first line segment you draw will remain horizontal and will be the axis of rotation.  Draw your Slab accordingly.

[David_W_Koch · Accepted solution]

Moving the pivot point will shift the axis of rotation, but it will always remain parallel to the first line segment drawn, even if you edit the vertices such that the angle of that first segment is changed.  The Slab will remember the original orientation and maintain an axis of rotation parallel to the way the first segment was initially drawn.

[R_Tweed · Accepted solution]

To have the option of selecting an edge for your pivot during slab creation, do not draw the slab point by point.

1. Draw a polyline to represent the boundary of the slab

2. Right click on the slab tool and use option apply tool to linework.

3. Select slab justification per the command prompt

4. Select the pivot edge. (this edge cannot be rotated later and is the basis off your pivot)

You might want to consider changing Aec display resolution for this drawing.  Changing the values below will make your arches and curved slabs smoother. Facet deviation smaller, Facet maximum larger.

[R_Tweed · Accepted solution]

Looking back at my earlier post.  You can rotate your pivot point. (sortof).  Below is clip of a slab with the pivot on the front so that the slab will slope in the direction of the arrow.

Rotate your slab and add a  shape for the new outline.

Use the slabtrim function and the slab will slope in the direction of the arrow but the pivot point will not be parallel to any two points.

Some things to consider. The  slabtrim  command will trim vertically if the slab is pitched. The outer curve was made with the slab flat and the inner hole using slabaddhole with the slab pitched.

[Wolfgang_Schau · Accepted solution]

They key was your remark about the baseline of the slab. This solved all my slab issues 🙂 Thank you very much. 

I would have loved a remark like that in the online help. You made my day!

[Wolfgang_Schau · Accepted solution]

David,

you nailed it! 

It solved my problem

[Wolfgang_Schau · Accepted solution]

Thank you, this was my problem and you helped me solving it now 🙂

[Wolfgang_Schau]

I am designing a slab for a balcony with a 1/8:12 slope, but I want the bottom remain horizontal, i.e. the thickness needs to be adjusted along the slope. 

How can I do that? 

[David_W_Koch · Accepted solution]

@Wolfgang_Schau 

One way:

Create a Slab with no slope, that is at least as thick as the thickest part of the balcony slab.

Create a Mass Element with a bottom face that slopes at 1/8" per foot (or whatever slope you want).  Size the Mass Element so that it will completely cover the Slab, and position it so that the bottom face of the Mass Element represents the desired top plane of the Slab.

Add a subtractive Interference Condition to the Slab, specifying the Mass Element as the interfering element.

Put the Mass Element on a layer that can be frozen, and freeze that layer.