Hollow Core Precast Slab - Custom Width

[Anonymous]

Hello All

I have downloaded a Hollow Core Precast Slab from the Autodesk Seek, and have modified it so that when I put the precast slabs on plan I am able to flex the slab to a custom width. I have already modified the family to flex and is working however, the cores that were drawn retain their original position and do not move when i flex the edge of the slab. In one of the end views you will see in the attached jpeg.

can anyone tell me how to set the core offset dimension to be linked to the end of the edge of the slab.

Thanks

Kevin

[Anonymous]

Did you check the assigned constraints?

[haydenwse]

You need to modify the family so that the first core is offset from the edge and the repeating cores are offset from the first one.  See attached.

[Anonymous]

Are the cores part of an array?  I have seen instance where the array was not labeled correctly in the family...the creator simply forgot to do it etc. 

[Anonymous]

I have provided the pc slab custom family I want to create. I got part of it work but I am having problems as described below. I know how to make families but I am still new to revit so please bear with me.

I am able to flex the width of the pc slab however when I do this, the pc slab that i am modelling will base the width on the centre of the slab. I do not want to do this. I want to be able to model this custom pc slab based on one side and have it offset 4'-0" (default for now) then I will flex the slab in my model itself. i have checked the width dimension and changed to an instance parameter. I have moved one side of the pc slab in the family to have the left rp be aligned to the centre-front/back rp. (see left elevation in family).

The project i am working on does not have any typical projection and indentations.

Also I want to have the family remove any cores as the slab gets smaller.

the file "Hollow Core-custom-width.rfa" is the revised family of the extrusion within the main file which is "Precast-Hollow Core Slab-custom-width.rfa"

Any help and suggestion welcome because I am stumped.

Thanks in advance

Kevin

[haydenwse]

The problem that you are having is that the standard family is based on an array and sets the core distance from each edge.  That is not the way that hollow core is cast.  You need to modify it so that it sets one edge and fixed distance to the subsequent cores. 

[Anonymous]

so tell me what steps i need to do.

[haydenwse]

The standard way that the out of box Revit families build the arrays is by using “move to last”.  For hollow core this is not correct.  The distance to the 1st core is fixed.  The offset to each additional core is fixed.  You need to change the core array so that it is based on the cell to cell offset.  I also calculate the number of cores with a simple equation.

[Anonymous]

Would someone have the answer to this question: why is it that when I am making multiple copies of a pc slab that the adjacent slabs would either disappear, move, or shorten. I am stumpped

[haydenwse]

I ran into the same problem on a recent project.  The problem was that the automatic concrete trim was not working properly.  It was not trimming to each of the beams that the hollow core was bearing on.  The solution was to use the “pick support” tool when building the beam system and select each beam.  I had picked one beam then used trim to join the corners. 

One other trick I found when using ripped planks was to use the new Layout Rule “Clear Spacing” with the distance as 0”.  When you put in a ripped plank it will readjust the layout using the actual width of each plank.

Hope this helps.