BIM elevations: lines between adjoining building elements?

[Markus Barrera-Kolb]

When generating elevations from a building model, how can you aviod seeing lines between, say, floor slab elements and the walls above and/or below (or between abutting wall sytles)? I'm using elevation viewports with an Open GL background render and a hidden line foreground render.

[CipesDesign]

First let me say that I feel your pain. Second, that NNA has made huge improvements in Hidden Line rendering, but are not all the way there yet. There are some specific things in 2009 that would help you - like the ability to assign a discreet texture to the edges of floor objects....

But since you're using 2008, here are some comments, and some workarounds...

1) Vertically stacked walls MUST be exactly aligned in plan view, and cannot be interrupted by floors. Therefore, make the walls below taller by the floor thickness and then either a) reduce the floor size to hide its edges, or b) put the floor in it's own layer (or class) which can be invisible in the elevation VP's.

2) Colinear (horizontally aligned) walls are a problem. The only solution I have found is to make the entire length of wall as one wall (using fit to roof or reshape to add needed stepping as req'd). Alternately, you can use a very thin extrude (in it's own class) with openings cut out and placed just in front of the offending wall. This method is not my fave because it req's redrawing the things when changes are made.

Hope that helps...

[billtheia]

As Peter said, perfect alignment is the key.

I have found that changing the rounding precision (File>Document Settings>Units - General Display tab) to 1/64 & .0000000001 makes this easier. I also have a script that toggles line weight on and off - I toggle it off to make sure that I'm snapping to the right place.

I've had SOME luck with horizontally aligned walls. One trick that seems to work pretty well is to draw the full length of the wall and then cut it into pieces as you need. Hidden line is really sensitive to the way that walls are cleaned up too. I have found, for instance, that three way intersections are the biggest pain. If you want walls to appear as one in elevation, you really need them to have abutting ends.

[Markus Barrera-Kolb]

Thanks for the responses Peter & Bill -- so if I still want to have a separate slab layer and keep my walls the same height as the actual stud walls (in platform-frame construction), I could draw walls on the slab layer the same height as the slab -- as long as they align perfectly with the walls above & below. Is that right?

Bill, I also made a script that allows me to toggle between, in my case, no line-thickness, black background, and zoom-line-thickness, white blackground, black & white only (kind of like a preview mode) -- use it all the time.

Let's hope that this aspect of VW keeps improving, especially for those of us who would like to implement BIM...

[billtheia]

...so if I still want to have a separate slab layer and keep my walls the same height as the actual stud walls (in platform-frame construction), I could draw walls on the slab layer the same height as the slab -- as long as they align perfectly with the walls above & below. Is that right?

Yes, BUT you won't be able to apply any texture to the slab edge. This is not a problem if you only want to do hidden line rendering but it is a problem if you want to render exterior finish materials.

VW's "standard" (what you'll see If you use the Model Setup Tool) is to set the top of wall elevation to match that of the top of slab above. Of course, this isn't the way that it would be built but it gets around the problem of no texture on slab edges AND it makes for one less thing to worry about aligning.

I fought it at the beginning but have caved to the VW way and it's been working pretty well. If/when I upgrade to 2009, I'll have to reconsider because, as Peter mentioned, '09 allows textures to be applied to slab edges.

[Markus Barrera-Kolb]

Well, based on your advice, here's what I came up with: instead of increasing the wall height to include the thickness of the floor above, I've drawn a wall of the same height around the floor object perimeter using a wall style representing only the wall sheathing and cladding. (I'm drawing the floor object to represent the dimensions of the framed floor: joists, rim, & subfloor.) And, as you indicated, in elevation this short "wall" segment blends seamlessly with the wall above/below. This way I can still use a worksheet to extract data on the walls as they would be actually framed, for instance for material take-offs, and can choose whether to include the portion of the wall at the floor thickness or not. Thanks again for your help!