Negative angles for roofs

[Kool Aid]

Once again, I lost a prospective user because of the McMansion -myopia of NNA.

It is not possible to design flat roofs with VW with any ease (not even with 3D-snapping) since roof faces still cannot have a negative angle.

For the information of NNA: in many countries flat roofs are the standard and even in Finland, at least the top levels of multi-storey car parks have flat roofs. There are places and situations where a flat roof is used as a rain water collector. And so on.

No, it can't be flat-flat: there needs to be drainage. That needs to be at least notionally shown in sections.

[CipesDesign]

Yes, this should be possible. Has it been officially Wishlisted? If not, it should!

[mike m oz]

A flat roof capability is needed.

In the interim you can create flat roofs with falls using solid subtractions of multiple extrudes from a zero degree Roof Face object or a Floor object.

[CipesDesign]

Hi Mike, et. al., It's actually quite easy to do with Roof Faces. You just need to designate that the pitch go "up" in the desired direction. See attached...

[Kool Aid]

Not all flat roofs are simple rectangles? Try the same with a polygon-shape with even 10 or 15 vertices and varying angles.

(A Roof is in fact a group of roof faces.)

[mike m oz]

Kool Aid the solid subtraction workaround is not ideal but as long as you ensure there are no reentrant corners creating self intersecting geometry it works.

[mike m oz]

Another method to create the subtracting object:

- Create a Roof object with the slope you want from a 2D Polygon.

- Convert it to a Group and Ungroup it to the Roof Face objects..

- Select all of the Roof Face objects and Convert them to a Mesh.

- In a Front View Rotate the Mesh object through 180?.

- In a Top/Plan View mirror the Mesh Object (If you have done this correctly the Mesh object will coincide with the original polygon).

All you need to do then is elevate the Mesh object relative to the 3D roof extrusion and do the Solid Subtraction.

[Kool Aid]

All these are horrible ? but oh so typical - workarounds! I can't tell a prospective user, who is looking at ArchiCAD, Revit & VW, to do things like that.

OK. Rolled my own. Here's the prototype. In hindsight, the approach is better as the roof is created from arbitrary triangles, with drain where-ever, as in reality.

[mike m oz]

I had assumed the need was for a flat structure with the graded falls formed by shaped insulation or a grano build up.

[Kool Aid]

Yes, of course. I just want to test the approach first before entering the realm of insulation, waterproofing and such: to check how long it takes to triangulate a complex roof manually.

[brudgers]

Another method to create the subtracting object:

- Create a Roof object with the slope you want from a 2D Polygon.

- Convert it to a Group and Ungroup it to the Roof Face objects..

- Select all of the Roof Face objects and Convert them to a Mesh.

- In a Front View Rotate the Mesh object through 180?.

- In a Top/Plan View mirror the Mesh Object (If you have done this correctly the Mesh object will coincide with the original polygon).

All you need to do then is elevate the Mesh object relative to the 3D roof extrusion and do the Solid Subtraction.

How about create a roof object with the slope you want... place in class1

Group it.

Duplicate it in place.

Convert the duplicate to 3d ploy's and place in class2

Mirror it in front view.

Now you have an inverted copy of the roof object.

You can recreate the inverted copy from the initial roof object fairly easily since both a positive slope roof and a negative slope roof look the same in plan.

Edited December 9, 2009 by brudgers

[Kool Aid]

Most definitely another useless workaround.

Well, that was fun!

Plan:

Edited December 9, 2009 by Kool Aid

[CipesDesign]

I think there are two main points to this topic: 1) We would all really like the ability to use negative slope values for roofs and roof faces; 2) Even so, there are a few ways to accomplish the task in a relatively pain free fashion. I would contend that although #1 shows a lack of functionality, #2 shows a great deal of versatility. For me it's an acceptable balance for the time being.

Kool Aid: I ask again, have you posted this to the wishlist? I can do it if you want, but it might be better received from you!

P

[Kool Aid]

Isn't this the wish list?

Nothing from me is well received at NNA: their stated policy is that only requests made in a grovelling tone are considered.

Edited December 9, 2009 by Kool Aid

[CipesDesign]

You're right - this IS the wishlist..... Thanks!

[brudgers]

Most definitely another useless workaround.

Well, that was fun!

Plan:

If you didn't know it was a workaround going in, I can understand your surprise at its uselessness.

Otherwise, I can't.

At least it's easier to create something useless.

[Kool Aid]

I'm sure that 99% of members understood that the reference was to your ?solution?.

My tool will, when finalised, to be extremely useful. As my tools always are.

[brudgers]

I'm sure that 99% of members understood that the reference was to your ?solution?.

My tool will, when finalised, to be extremely useful. As my tools always are.

I doubt 99% of members have read the post.

But I understood your comment as refering to my solution as well.

However, my post was related to the proposed workaround with the goal of producing similar results more quickly.

Never would I imagine that anyone's post (let alone mine) has met your requirements.

[Kool Aid]

I'm almost there. Now I can have either a traditional, ventilated flat roof or a reversed one (eg. trafficable roofs).

Turns out that creation of the roof segments this way is acceptably fast: draw a line, move a point.

So, my wish has been granted! (Well, the actual wish still is ungranted and pending, but I have a solution to the problem at hand.)

[brudgers]

Here's another workaround, which suggests how a negative slope roof tool ought to work:

1. start with 3d loci.

2. Create a site model.

3. Use "create 3d mesh solid."

4. Create a snapshot.

5. convert snapshot to 3d polys.

6. Ungroup

7. create solid addition from 3d polys.

8. create solid subtraction from solid addition when plan is concave.

Editing the site model loci and modifying the solid subtraction are fairly trivial because you have the site model as a control structure.

Edited December 11, 2009 by brudgers