Modeling Roofs

Multiple Roof Lines

The roof object can be controlled using several roof lines. To try this, take a top view, activate the building tool and draw the walls as shown in the picture.

After drawing the walls, hit the roof tool button. It appears to the second row of the toolbar automatically when a building object is selected. The roof tool adds a default roof to the building. In this case, the default roof is a pyramid-like symmetric hipped roof.

Draw cross-like walls

The roof becomes automatically selected, and its context tool Roof Line appears to the tool bar. Click the Roof Line tool. From the top view, draw a straight line across the building as shown in the picture. Click Accept or hit the Enter key after clicking the second point.

The first roof line

Note that the first roof line does not change the roof at all. It is still a pyramid like hipped roof. Activate the roof line tool again and draw a second line, which is perpendicular to the first roof line, across the building.

The two guide lines together define a cross-like roof.

The second roof line

Editing the Roof Manually

Automatic roof builder provides a quick way to add the roof. However, it is quite limited. The automatic roof object can be used as a starting point for modeling unusual roof shapes.

Select the roof object created in the example above. Open the property window (using 'p' hotkey or from the popup menu). Deactivate the Build option. Automatic roof construction is now disabled, and you can start editing the shape.

Select the object called 'subdivXX' in the sub folder called 'roof' of the roof creator object.

The roof surface selected

The second toolbar row shows an Edit mode control; set it to the Point mode. Then scroll the second row of the toolbar until you find the Knife tool. Click the tool to activate it. Take a front view and draw a horizontal line across the roof as in the picture below. Hit the Enter key after clicking the second point.

Cutting the roof top with the knife tool

Select the topmost points of the roof by LMB-dragging a selection box around the roof top. Move the pointer exactly on top of a selected point handle, press the left mouse button down and drag the points upwards about one meter. Be careful not to drag the blue handle lines - it will break the roof!

Move the roof top upwards

The modified roof is now ready. To improve rendering quality, open the UV editor from the Windows pull down menu and move the selected points further away from other points to compensate texture stretching, which appeared when the roof surface was stretched upwards.

[Note] Note
Enabling the roof's Build option removes all manually edited changes from the roof.
Oriental roof style

Custom Roof Shapes

The whole roof surface can be modeled manually. Placing the custom roof surface into the hierarchy of the roof builder object allows some automatic parametric features such as wall fitting with the roof.

We will continue from the tutorial above. If you experiment with another building project, just make sure that Build option of the roof object is turned off. Select the sub folders roof, layer2 and layer3. Hit the del key to delete them. This removes all roof surfaces.

Take a top view. Activate the SDS/Rectangle tool from the toolbar. Draw a rectangle that is about 1 meter wider than the walls. From the front view, move the rectangle above the building.

Go back to the top view. Apply the SDS Knife tool 4 times to cut new sections through the SDS rectangle, as shown in the example picture.

SDS rectangle forms the roof
Corner faces selected

Set the Edit mode selector in the toolbar to Face. Click a corner face and then shift click the three other corner faces to multi select them.

Hit the Destroy tool button in the toolbar to remove the corner faces.

Set the edit mode selector to Point. Select the SDS points one by one from the top view, and apply the move tool (m hotkey) from the side and front views to move the points up and down, so that the SDS surface gets an irregular bumpy shape. Note that holding the y modifier key down while moving keeps the roof points on their original vertical axis.

Set the Edit mode back to Face. Apply the Dupl tool (Duplicate Faces). Hit m hotkey, press y modifier down and move the duplicated faces slightly upwards. The roof gets some thickness.

Roof points edited vertically

The top layer of the roof is now suitably selected. Take a top view and zoom in heavily so that you see only a small part of the roof (one texture tile). Switch to the materials tab and drag and drop the material buildingX_roof to the view window. This assigns it to the selected faces. Open the property window and select a suitable texture map for the buildingX_roof material.

Switch back to the geometry tab of the select window. Go to the spec tab f the property window and change the Rendering/Type of the SDS object to Smoothen to NURBS. The roof gets an organic rounded shape.

Set the SDS Edit mode to Edge. Multi select outermost edges of the top and bottom surfaces of the roof - see the picture below. You can do this easily from the top view. Just keep the Shift key down and drag small selection boxes which hit the desired edges. Do not select the short vertical edges at roof corners.

Set the rounding selector at the right end of the second row of the toolbar from Round to Sharp. You can make the edges sharp also using the controls available in the Spec tab of the SDS property window.

The roof edge loops selected

The roof is now ready. Set the Edit mode to Object and drag and drop the SDS object from the root level into the hierarchy of the roof object. It can be placed anywhere in the roof's sub hierarchy.

Select the Wall0 object in the wall definitions folder of the Building object. Activate Extend to Roof option from the toolbar. Walls expand up to the roof. To ensure accurate match, change the fitting density of the wall object to 0.1 meters from the toolbar.

Gaudian roof style?