They have the strangest names: gable, hip, jerkinheads, clerestory, sawtooth, witch 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 due to their complexity, even traditional ceiling drafting is generally recognized as one of the most challenging skills to master in architectural design drafting. Both Revit and AutoCAD are well equipped to allow delivery of these roof designs in residential design drawings, but for many, AutoCAD is getting a little ahead of it.
Since the time of the Stone Age, having a roof over our heads has been one of life’s highest priorities and a recognized human right. 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 designed on their own, or they can be created as a result of placing them in a space that has been delimited by a polyline or set of walls. Once defined, the dimensions, slope, 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 edging 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 fancy names, the basic types include gable, hip, shed, or flat. Inexpensive and easy to build, the sloped gable is the most common type worldwide. Due to its slope, rain and snow are not retained and leaks are prevented, increasing its durability. The ‘hip’ has slopes on four sides, which helps it 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 inclined 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 combinations of gable, hip and other combinations.
So how are AutoCAD and Revit doing 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, planes must be contrasted with elevations and ridges.
The commands in AutoCAD for creating different layouts are versatile. They can be changed individually with changes in height, slope, edges, and the addition of dormer windows. A simple contour can be drawn as a polyline of a group of walls, which can be turned into a ceiling, so that the draftsman can focus first on the contour and then on modifications.
Flats and slopes can be created with the same process, with a low height number and a 0 “overhang for the floor. Points on the inside 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 angle, climb or run off slabs, and can help create gables.
You can define materials. They can be displayed in wireframe and working shadow views.
Features of ceiling design drafting in AutoCAD include:
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Tool properties for an existing one
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Changing dimensions
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Change edges and faces
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Slab conversion
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Select material
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Select display properties
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Select hatching
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Change of location
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Attach hyperlinks, notes, or files
Revit
Designing a ceiling in Revit is considerably different from doing it in AutoCAD. Revit is considered best for large-scale projects and has many options. Although the plan and elevation tool is effective, drafting sections and other details can be challenging, especially for traditional homes with sloped, sloped, curved, cranked, and custom-built 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 be where expected. 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 mass faces, 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 includes shape editing tools. Once the lines are drawn, the default 3D view can allow adjustment of shape, height, and movement, but this way it cannot be attached to another roof.
In Revit, a roof can be created from: a building footprint, such as an extrusion, with sloped glazing, or from a mass instance, but it cannot pass through doors or windows, although trusses can be attached in the design.
Create by footprint implies:
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2D closed-loop sketch of the perimeter
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Select walls or draw lines from plan view.
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Closed loops for openings
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Slope Parameters for Sketch Lines
Creation by extrusion involves:
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An open loop sketch of the profile.
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Use lines and arcs to draw the profile in an elevation view
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Edit the work plane
Challenges with drafting the ceiling design in Revit
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When creating a hip rafter construction (for a vaulted ceiling), Revit does not automatically allow a ridge post or other support element to support the hip intersection.
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The individual elements of a design are placed on the same plane.
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It is more difficult to edit.
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With changes in the reference levels (for example, elevations), other dimensions must also be modified.
When comparing the ceiling design drawing capabilities of AutoCAD and Revit, users feel that AutoCAD is easier to use because:
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Create and modify contours with more control
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Makes it easy to add details and options.
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Makes editing easy
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Facilitates writing and documentation
However, Revit modeling allows draftsmen with fewer architectural or technical skills to produce more complex designs, whereas in AutoCAD, precision and accuracy is entirely dependent on the ability of the draftsman to correctly interpret the design.
Ultimately, although Revit and AutoCAD software have extensive tools for roof design, it is AutoCAD’s easy-to-use general approach that residential drafting service professionals have found to be slightly more preferable.
