Roof Design Drawing – Revit/AutoCAD?

They have the strangest names: gable, hip, jerkinheads, clerestory, saw-tooth, witch’s hats, karahafu, mansard, rainbow, butterfly, satari and many more. No, they are not a list of insect species. They are the names of different styles of roofs. Although the various designs must be handled with care because of their complexity, even drawing the traditional roof is generally recognized as one of the most difficult skills to master in architectural design drafting. Both Revit and AutoCAD are well equipped to enable the delivery of these roof designs in residential design drawings, but for many AutoCAD is a bit ahead.

Since the Stone Age, having a roof or shelter has been one of life’s highest priorities and a recognized human right. The designs have come a long way from the rudimentary designs of yesteryear. So how does it work and what are the basic designs?

Ceilings can be drawn on their own, or they can be created as a result of placing them in a space that has been enclosed by a polyline or set of walls. Once defined, the dimensions, slopes, faces or edges can be modified. For more complex designs, an ‘object’ is selected and modified until it is almost complete. For greater flexibility in customizing edges and other features, the ceiling can be converted into slabs, to which many details such as orientation, angle, fascia, and soffit profiles can be added or changed. These design details can be added globally.

Aside from the more complex ones with the fancy names, the basic types include gable, hip, shed, or flat. Cheap and easy to build, the sloped pediment is the most common type throughout the world. Due to its slope, rain and snow are not retained and leaks are prevented, which increases its durability. The ‘cuatera’ has slopes on four sides, helping to anchor the house below it. They are less affected by high winds and can be added to a new home or an existing home. A ‘shed’ features only one sloped plane, which may have skylights or solar panels, increasing the potential for energy efficiency. The ‘flats’ are almost completely horizontal with a slight slope for drainage, favorable for solar panels and cost effective. There are also gable, hip and other combinations.

So how do AutoCAD and Revit fare in the roof design drafting process?

autocad

AutoCAD software offers a variety of options for creating and modifying a wide range of styles. In AutoCAD, plans must be checked against elevations and ridges.

The commands in AutoCAD to create different layouts are versatile. They can be changed individually with changes in height, slope, edges and the addition of dormers. A simple outline can be drawn as a polyline of a group of walls, which can be converted to a ceiling, so the drafter can concentrate on the outline first and modifications later.

Flats and slopes can be created with the same process, with a low rise number and 0″ overhang set for the flat. Points on the interior of the exterior walls are chosen so that the tops of the walls form parapets .

The ‘Properties’ palette can change the thickness, pitch and overhang.

AutoCAD ‘grips’ allow editing in such a way that 2D objects such as lines, polylines and arcs can be stretched, moved, rotated, scaled, copied or mirrored. Grips can also change edges and vertices, ridge points, fix missing intersections, change the angle, elevation, or run of slabs, and can help create gables.

Materials can be defined. They can be displayed in wireframe and work shadow views.

Features of roof design drawing in AutoCAD include:

• Tool properties for an existing one
• Change of dimensions
• Change of edges and faces
• Slab conversion
• material selection
• Selection of display properties
• Shading Selection
• Change of location
• Attach hyperlinks, notes or files

relive

Designing a ceiling in Revit is considerably different than designing it in AutoCAD. Revit is considered best for large-scale projects and has many options. While the tool for elevation views and plans is effective, drawing sections and other details can be a challenge, especially for traditional homes with sloped, pitched, curved, cranked, and custom units. When creating complex roofs in Revit it may be preferable to create them as separate units and then join them to the other section with the ‘join roof’ tool.

Usually it may not be aesthetically appealing and the edges may not meet where you expect them to. This usually happens because Revit tries to develop slopes from the edges. The edges may not come together perfectly, and there are a few ways to counteract this problem. One way is to create a mass, select the faces of the mass and create a roof. This could be tricky and time consuming as a slope arrow must be used to change the angle and direction of the slope.

Another option involves shape editing tools. Once the lines are drawn, the default 3D view can allow adjustment of shape, height and movement, but in this way, it cannot be attached to another roof.

In Revit, a roof can be created from: a building footprint, as an extrusion, with sloped glazing, or from a mass instance, but cannot span through doors or windows, although trusses can be attached to the design.

Create by footprint implies:

• 2D closed-loop sketches of the perimeter
• Select walls or draw lines from plan view
• Closed ties for openings
• Slope Parameters for Sketch Lines

Creating by extrusion involves:

• An open loop sketch of the profile.
• Using lines and arcs to draw the profile in an elevation view
• Editing the work plane

Challenges with drawing the ceiling design in Revit

• When creating a hip construction with beams (for a vaulted ceiling), Revit does not automatically allow a ridge post or other support element to support the hip intersection.
• The individual elements of a design are placed on the same plane.
• It is more difficult to edit.
• With changes in reference levels (for example, elevations), other dimensions must also be modified.

When comparing the roof design drawing capabilities of AutoCAD and Revit, users find AutoCAD easier to use because:

• Create and modify contours with more control.
• Makes it easier to add details and options.
• Make editing easy
• Makes writing and documentation easy.

However, Revit modeling allows drafters with less architectural or technical skills to produce more complex designs, while in AutoCAD, precision and accuracy depend entirely on the draftsman’s ability to correctly interpret the design.

Ultimately, although Revit and AutoCAD software have extensive tools for roof design, it is AutoCAD’s overall easy-to-use approach that residential drafting service professionals have found to be slightly more preferable.