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BIM - Slabs


zoomer

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Who uses Slabs ?

What are the advantages of Slabs over a simple Extrude beside having

a BIM Slab Tag and the ability to bound 1 (!) level to a Story level ?

Bounding to Walls works in most simple environments only.

As soon as part of the Slab should overlap the Walls, like when you Floor Plan

of your Story is overlapping but not same as the Walls of the Story below.

Then you have to also draw your shape manually.

Picking Walls isn't very convenient anyway.

You can only bound the Z-Ref to a Story level, the Thickness will be hard coded

into the Slab Style. No flexibility when changing Height Levels

In 2016 you still can't see your environment when in Slab Editing Mode.

Means you have to draw your Stair Holes, CMD+X, before you edit the Slab and

need to paste in.

For changes you have to Edit Slab and delete the previous modifying geometry

before pasting the new one, otherwise you will forget which geometry is needed

and which not.

If you have a Slab and want to get rid of it by CMD+U, you will not get a simple

Extrude as you expect but a Floor Object. Bottom Z in OIP is shown relative to

the active Layers Story Height !?

If you CMD+U the Floor Object, you will at least get your 2D boundary object.

But in 2016 it will jump in Height to World Z 0.00, when you were on a Layer

with a Story Height.

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I use slabs all the time.

The reasons I use them are

1. Unlike extrudes, have a fill in 2D that can be a hatch if you want. Especially in structures that have some rooms open to the floor below, using a slab to occlude the floors below is great.

2. They are much easier to edit than extrudes using add surface and clip surface. (To cut stair holes you can draw a rectangle and clip surface.) Not sure what you mean by deleting geometry and pasting… I usually use the X-ray command (B) to see the geometry on the floor below when drawing the slab cut out, then select the slab and the geometry and clip surface.

3. It's easy to quickly lay down some framing members using the framing command. Can't to that with and extrude. :)

If you ungroup a slab, I believe you get one polygon and one floor object for every component of the slab. (Like a proto Auto Hybrid object) I agree that it's odd that floor object heights are from the bottom of the object and slab objects are from the top. I prefer to think of the top of the slab height rather than the bottom of the floor height.

4. The ability to pick new boundaries for slab objects it pretty slick. I agree that we need more control with boundaries. Go under this wall but not that wall. For simple buildings or for just getting started I find using auto boundaries is great. But it doesn't take a lot of complexity before you need manual slab boundaries.

hth

mk

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Thanks Michael,

So there is one ;)

1. Unlike extrudes, have a fill in 2D that can be a hatch if you want. Especially in structures that have some rooms open to the floor below, using a slab to occlude the floors below is great.

Ah, forgot about that.

(Remeber a video of a spotlight user using Slabs instead of Walls or Extrudes because

of this fact for his theater)

2. They are much easier to edit than extrudes using add surface and clip surface. (To cut stair holes you can draw a rectangle and clip surface.)

OK, trick #1

I would not have expected that option (2D tool on 3D Object)

Seems to work fine.

Not sure what you mean by deleting geometry and pasting…

I think I learned how to edit Slabs from a tutorial.

Like elsewhere, double clicking on a Slab to go into edit mode (like a Symbol),

and boom, everything else is invisible and nothing to snap or orient anymore.

I agree that it's odd that floor object heights are from the bottom of the object and slab objects are from the top. I prefer to think of the top of the slab height rather than the bottom of the floor height.

+++++1

4. The ability to pick new boundaries for slab objects it pretty slick. I agree that we need more control with boundaries. Go under this wall but not that wall. For simple buildings or for just getting started I find using auto boundaries is great. But it doesn't take a lot of complexity before you need manual slab boundaries.

+1

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That add and clip surface trick works on roof faces and floors as well. (although there is a small bug in add surface with roof faces in 2016)

When you double click a floor object to get back to it's original polygon or polyline, if "show other objects while in edit mode" is on, then you should be able to still see and snap to other objects in the drawing.

I also use floor objects for countertops. They can be edited with clip and add surface the same way. Easy to control the height and thickness with parameters. I don't like the way the countertop is split up in 2D when using the countertop on the base cabinet tool. And with a floor object it's easy to cut a hole for the sink or add extensions for islands.

mk

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When you double click a floor object to get back to it's original polygon or polyline, if "show other objects while in edit mode" is on, then you should be able to still see and snap to other objects in the drawing.

That does not seem to work for me, like it works for Extrudes or Symbols, since VW 2014.

As I thought this is the only way to edit Slabs, working blindfolded, I had to draw my

2D cutting Geometry before and paste it in the blindfolded Edit Slab mode.

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Ok, thanks to Michael's coaching,

Slabs are sorted into my list of useful Tools in VW now and I will keep the

Slab Styles that I have created so far for my Template File.

Next question, Slab Styles.

So far I tend to set all my Styles and Plugin Symbols to have everything assigned

by Component and Class to keep everything "parametric".

I realized that will limit to 2,5D Materials for the Slab case.

Do you use Material by Object, to assign different (wall) Materials to the vertical

Sides or any other tricks in practice ?

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Now were talking philosophy!

Since I'm a hired gun I have to adapt to the graphic standards of whatever client I'm working for.

At the moment, none of my clients wants components in walls or slabs for graphic reasons.

When I'm doing my own thing, I like to do it by component and have the components use class attributes. Again for graphic reasons - it makes adjusting fills and line weights easier, since each project gets sent to a different print house. After the first print, we can make graphic changes more quickly that way than editing the definitions of walls, slabs, and roof objects.

But for smaller projects, you can't beat the simplicity of single component wall and slab styles with the graphic attributes assigned in the definition. I usually apply textures to the left side of the exterior walls and call it done.

I'm trying to talk some clients into using stories and wall components so we can apply ledges and have the exterior cladding of exterior walls cover the slabs.

But for now, I'm happy everyone is using worksheets :)

mk

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Hello People's,

If I may weigh in...

Generally I will use by component, but there is no absolute rule whether to assign material by object or by component. At the start of a project, developing components for walls and slabs can take time, so I might assign by object, but as it progresses, I will move over to by component. Also I will often assign existing walls and buildings to by object, as I will render them in a dark grey, as so they may stay by object for the full duration of the project.

For components I use a "Component-..." series of classes that relate to finishes/materials. For example, it doesn't matter if a concrete material is used in a wall or a slab etc, as long as it has the same finish (texture) I will use the same class.

For the settings of these classes, I have preset colours, line weights, hatches, textures etc so that if I render in 3D, cut a section in 3D, or drawing a 2D detail, the same class is used.

Why do this? The benefits are that there no longer are wall, slab, stair, roof etc component classes, just material and finishes classes. Also these classes can relate directly to my finishes schedules.

PS I also use floor objects for a multitude of 3D work that needs to read correctly in 2D. As mentioned above, kitchen benches are a great example.

Hope that helps.

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Bounding to Walls works in most simple environments only.

As soon as part of the Slab should overlap the Walls, like when you Floor Plan

of your Story is overlapping but not same as the Walls of the Story below.

Then you have to also draw your shape manually.

Picking Walls isn't very convenient anyway.

I don't know how you bind your walls, but I never have this problem. You have to bind to the correct walls. Know that you can bind to walls on other layers (when you have the option '../modify others' on in the layer options.)

Also, if you can't bind your slabs, then it can be that your drawing methodology isn't great and maybe you should revision it. I'm especially talking about flat roof sections from the story below: I draw those top parts of the walls separate, that makes it way easier to work with, and avoid problems like binding to walls...

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You can only bound the Z-Ref to a Story level, the Thickness will be hard coded

into the Slab Style. No flexibility when changing Height Levels

True, and that's the same shortcoming that walls have. Imho a slab/wall/roof style should be about the kind of components, not about their thickness...

But I don't see the problem when changing height levels. A slab shouldn't be determined by two heights, it sits at a height and has a thickness...

Edited by Dieter @ DWorks
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In 2016 you still can't see your environment when in Slab Editing Mode.

Means you have to draw your Stair Holes, CMD+X, before you edit the Slab and

need to paste in.

For changes you have to Edit Slab and delete the previous modifying geometry

before pasting the new one, otherwise you will forget which geometry is needed

and which not.

You can just add and subtract shapes without going into the 'edit slab holes' mode. But yeah, I also hate it to have artefacts of previous adds/subtractions, so I also delete all and redo from time to time, though I don't have to add/subtract that many things, except for the door/window openings.

Imo, we shouldn't need to be able to do this, at least not the subtracting, a slab should make the holes itself through priority based stuff, so if a wall is intersecting it, cut the slab.... This is already on the wish list.

Edited by Dieter @ DWorks
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If you have a Slab and want to get rid of it by CMD+U, you will not get a simple

Extrude as you expect but a Floor Object. Bottom Z in OIP is shown relative to

the active Layers Story Height !?

If you CMD+U the Floor Object, you will at least get your 2D boundary object.

But in 2016 it will jump in Height to World Z 0.00, when you were on a Layer

with a Story Height.

VW has Z problems in different areas, especially related to stories. If you want to get the extrude, just go to edit shape mode, copy it, go back from the edit shape mode, past it, extrude it, change height if needed.

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Yes,

neither my projects nor my workflow may be compatible with VW in general.

But does someone use Slabs and is happy or even convinced of Slabs because

of things, workarounds or tricks I don't know so far ?

Yes! I'm very happy with slabs, they speed up the work, make great floor plans (because of the fill) and I get my sections almost complete for the first phases of the project. There are no real tricks to it. There are more tricks and workaround you need to know for the walls.

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I think I learned how to edit Slabs from a tutorial.

Like elsewhere, double clicking on a Slab to go into edit mode (like a Symbol),

and boom, everything else is invisible and nothing to snap or orient anymore.

you can edit the shape of a slab by selecting the slab, then select the edit polygon tool from your basic tool pallet, then you don't need to go into the edit mode...

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OK.

For my Template Styles I go a similar way.

Just the simplest Styles so that I can start drawing and do nice screenshots immediately.

I too don't use "real"components.

I will draw all Walls on "Class Walls-0" and but have set one Wall/Slab Component,

maybe Concrete, to be assigned to Class Wall-Concrete.

So maybe I will have 2 simple Styles like a classic modern White Plaster and a

more progressive Concrete Version.

No one expects serious 2D plans output from me but it should be possible to extract

nice reduced but plausible Sections, for me to control my modeling and for clients

to show/explain geometrical problems.

So Walls and Slabs of same Material should melt together in Sections.

I never found Slabs with more than one Component useful in practice so I always did

an additional Slab/Floor for the Finishing Floor. I think I should stay with Slabs.

I can bound these (Floor)Slabs to Walls of Rooms/Spaces

(Or do Floor Objects have any meaning I don't know so far ?)

If I got that right I should be fine with my 1-Component Walls/Slabs strictly by

Components/Classes. As I see I can still overwrite Walls/Slabs later to by-object

assignment in OIP later, if ever needed.

Edited by zoomer
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