Roof Design - what's the best way to accomplish this shape?

[rob2218]

here's what I have.
A "roof" element in the design which contains a large slab. tapered in a percentage of the slab.
it also has an end taper as well.
it contains multiple openings (slits if you will) and one large opening in the flat part of the slab.

what is the best way to model this roof object?
Currently we have a designer who has modeled this as a "morph" and has placed large mass objects all around to represent the subtraction of the holes.....
Now..I don't mind doing this but...you always have to have these "boxes" in a layer that is always turned off so's as not to see it.

Any suggestions on a better way of doing this shape with slabs or shells?

[Dwight]

That is there so you can see that the solution involves two slabs. The red one only has holes in it. The green/gray one is a duplicate of the red one [with holes in it] dragged down one thickness and the edge is tapered to 5 degrees.

[rob2218]

thanks all....I just learned how to open holes in "morph" object.
Very much like sketchup type function.
amazing how you can "push-n-pull" planes and shapes up and down and all around a shape...wow!

here's one question:
seems that when I push a morph objects pline area (the sketch pencil that's used when touching on a plane)...if I push that plane down to the bottom of the morph object....in anticipation of making a hole....seems that it tries to heal itself in an odd manner.

I've learned how to "subtract" one morph piece from another..therefore allowing me to make "holes" in a morphed object....again..pretty slick!

[Laszlo Nagy]

Here's all the feature clips about the Morph:

http://www.youtube.com/playlist?list=PL1196509B1C879ACD

Erich wrote:
Why not just do this as a slab with holes in the slab. For the taper place a temporary roof plane matched to the desired taper and use the Trim to Roof command. You can then delete the roof if you wish.

Erich,
I checked this and it does not give me the proper result as it does not create a tapered result, it just cuts off part of the Slab vertically; only Custom Slab Edge gives a tapered result, but that starts from the upper surface of the Slab.
You could do that by SEO, but then you would have to keep the Roof used for the SEO as operator (possibly on a separate, hidden layer).

[Laszlo Nagy]

Here is another solution: Shell.
I created a simple Shell the Profile of which is a straight line. I then used the Create Hole in Shell command of the context menu to cut the holes. You can create one for the thin ones, select it and multiply it.
Then I used the Define Shell Contour command of the context menu to define the shape of the Shell from the side. Originally this can be defined only in the horizontal plane. So I then had to select the Shell Contour and rotate it 90 degrees in a vertical plane and move it, adjust it so it cuts the exact intended shape. Voilá.

[rob2218]

Las,
now...when I tried the "shell" command, it' was asking me for a "thickness"? which specific "shell" command did you use?
how did you get the profile to be "solid" like that?
I must admit, I have yet to experiment with either the "morph" nor the "shell" command but I'm convinced they are great tools....just need to work with them a bit more.....but I digress....so what was the process you did to create that exact slab-type object I'm looking for?

[Laszlo Nagy]

I used a simple Extruded Shell with the simple method. Then I clicked the half-circle Profile Polygon and converted it into a straight segment. You can also draw a single line segment as the Profile Polygon and extrude it. The dark thick blue lines are the Profile Polygon and the Extrusion vector.
The thickness is the thickness you set in the settings dialog. The Shell is of a constant thickness. I did not create a "shell" of this structure that is hollow inside; it is a simple extruded shell, you can see it from the Profile Polygon and Extrusion vector how simple it is.

All the Shell videos on YouTube:

https://www.youtube.com/playlist?list=PL1CA38C58B1DCFE58

The videos needed for the steps:

Create Extruded Shell:
https://www.youtube.com/watch?v=Uv_2ur7GscA&list=PL1CA38C58B1DCFE58&index=2

Edit Profile Polygon:
https://www.youtube.com/watch?v=71nnlZSdVFQ&list=PL1CA38C58B1DCFE58&index=16

Define Contour Polygon:
https://www.youtube.com/watch?v=Pvc24yA4j5c&list=PL1CA38C58B1DCFE58&index=23

Define Holes:
https://www.youtube.com/watch?v=9ZzYj6CieKk&list=PL1CA38C58B1DCFE58&index=26

Edit Contour Polygon:
https://www.youtube.com/watch?v=TQ7Mtj8JuRg&list=PL1CA38C58B1DCFE58&index=24

Rotate Contour Polygon:
https://www.youtube.com/watch?v=W9xQm_BjJYw&list=PL1CA38C58B1DCFE58&index=25

[rob2218]

thanks, I'll have to study the videos.
I tried using that "half circle" (simple shell) shape command but I'm having trouble with the "thickness" issue.

it's asking me to give it a "thickness". I don't want to give it a thickness I want the entire pline shape to 'be' the shell's profile shape...but I'll simply have to play with a bit more.

too bad the shell command doesn't have a "magic wand" option where you can select a pline profile in plan view and extrude it alone a length in 3D view.

[Laszlo Nagy]

Are you sure it is thickness?
My ArchiCAD asks me for an Extrusion Length.

By the way, when you are using the Extruded Shell with the Detailed Method, when it asks you to draw the Profile Polygon you can just SPACE-click a polygonal element and it will take its shape.