Funky Roof corners

[Chris Rogers]

All of my roof corners display correctly in 3D wireframe view but are drawn with triple lines in 3D hidden and rendered views. Any ideas?

Drawing attached (I hope).

I am using 2008

[Chris Rogers]

If I can't get the forum attachment thing to work, there is no hope for me and BIM. Trying again...

[CipesDesign]

More info needed: did you create this with the Create Roof command? Or the Roof Face command? Did you Ungroup the original roof? Did you move roof faces? Did you perhaps duplicate some roofs or roof faces by accident??

[Chris Rogers]

I used the roof face command. I did lower some of the faces to a negative z axis because I have two different eave heights and the z elevation corresponds to the higher of the 2. I also use negative roof thickness because I want the edge of eave to control the height, not the plate bearing. I don't think I duplicated anything.

[D Wood]

It does look as though you might have duplicated faces, and negative roof thickness sounds like a no-no.

[CipesDesign]

Interestingly, although one cannot enter a negative thickness value during creation, one can change the value to negative after creation via the OIP. The result is as expected (ie: the roof is drawn below rather than above its bearing height). I suspect that the specific problems here are caused by inaccurate calculation of the angle of intersection of two roof faces with differing pitches(??).

I would approach this problem as follows: 1) In top/plan view draw the basic polygon which outlines the perimeter of the building; 2) Run the Create Roof Command using an appropriate thickness and either of the two pitches required; 3) Modify the pitch and bearing height of whichever faces of the roof need to be changed; 4) If necessary Ungroup the roof into its various Roof Faces and tinker, using Add/Clip Surface in top/plan to get the desired result.

NOTE: In order to properly use Roof Faces the user must be very aware of their unique properties, such as the line drawn during creation equals the line at which the bearing height is calculated, etc., etc... I often find it much easier to use the roof faces that are derived from an ungrouped roof as they are all in their proper places, as least to start with....