How to Use the CalcsCAD Automatic Framing Tool

The ClearCalcs CalcsCAD plugin allows engineers to quickly produce accurate and cost-effective residential framing computations in a fraction of the usual time. With the easy to use CAD plugin, simply tag the roof outline, walls, beams, and studs, and the CalcsCAD plugin will automatically determine tributary areas and loads, as well as create and automatically size all framing members in ClearCalcs.

This article details step by step instructions for how to draft a single and multi storey home using the CalcsCAD plugin. See our quick command reference guide for a brief overview of each command's function.

How It Works

The framing tool takes traditional 2D drafting and attaches ‘properties’ to line data so we can identify what is a beam, truss, roof etc. Using this information, we can automatically determine what the loads and supports are for each member, and as a result do the engineering for them.

N.B. At the moment, the CalcsCAD plugin only supports trussed roofs. Support for stick framed homes is under development.

In order to work, the framing tool requires the user to specify:

  1. Plan layers and alignment points
  2. Roof perimeter area
  3. Columns/studs
  4. All structural beams/lintels, connected by load bearing walls (N.B. Any beams or walls with ‘disconnected’ ends such as interior load bearing walls must have the end line ‘Allow Disconnect’ property ticked in the properties panel)
  5. All girder trusses (GT), hip trusses, and valleys
  6. Joist areas (for multi storey homes only)
  7. Any void locations (ex. stair voids) and area overrides (eg. solar panels, bathrooms)

One this is done, you may validate the drawing and export to ClearCalcs for automatic design.

Using the ClearCalcs CalcsCAD Plugin

The below steps outline how to draft a single or multi-storey dwelling using the CalcsCAD plugin. All of these steps involve drawing or tagging (converting) objects with CalcsCAD properties. As such, we recommend you keep the Properties (CC:PROPS) panel open and docked at all times.

While we generally recommend drafting as accurately as possible to ensure no errors arise, the plugin does have a 10mm/0.5in tolerance.

Displays the Properties pop up panel which allows the properties of a given selected object to be viewed and changed. If an object is selected that has no ClearCalcs properties associated, the panel will be blank.

1. Set Up Plan Layers and Alignment Points

By default, all new drawings will have a single 'Default' Plan Layer in the CalcsCAD ribbon which will also be the active layer. It is important to note that Plan Layers are independent of normal CAD drawing layers, so you may still maintain your own company specific CAD layers such as TEXT and DEFPOINTS. 

If you are drafting a single storey dwelling, you may proceed directly to step 2. If you are drafting a multi-storey dwelling, you will need to set up additional Plan Layers for each level (from top to bottom) and specify an Alignment Point on each layer to ensure the plugin can accurately overlay and align loads travelling down through the structure.

Plan Layers

All new objects drawn or tagged will be assigned to the active Plan Layer - denoted either by the top dropdown in the Plan Layers panel, or in the Plan Layers pop up. If you tag an object to the incorrect layer, clicking 'Set Plan Layer' with the object selected will re-assign it to whichever Plan Layer is currently active.

N.B. BricsCAD v18 does not support in ribbon drop downs, so the only way to change the active and ghost layer is to do so via the Plan Layers pop up panel (below).

Alignment Points

Alignment points are used by the CalcsCAD plugin to line up the various levels of a multi-storey structure so they sit on top of each other correctly when calculating loads, and to enable our Ghost layer function which allows you to overlay a semi-transparent copy of another level for easy checking.

You must add one Alignment Point per Plan Layer - for example, you may wish to tag the top left corner of each level.

Relevant Commands

Plan Layers
Opens plan layers dialog box where you can add new levels, and change the current active and ghost layer.
Alignment Point
Creates a POINT on the selected plan layer. You need to create one alignment point per plan layer (building level) to enable accurate load tracking and ghosting. These should both align with each other (i.e. the corner of a building).
Set Plan Layer
Sets the Plan Layer property of any selected object to match the current active plan layer. This can be used to quickly associate all beams with the ground level for example. It is useful if objects were mistakenly associated with the wrong layer.  

2. Draw or Convert Roof Perimeter Area

Specifying a Roof Perimeter area allows the CalcsCAD tool to determine all loads transferring from the roof down onto the trusses, columns, and beams in a structure. A Roof Perimeter must be a closed polyline. Please ensure the polyline you draw is closed otherwise the tool will not convert to a roof area. A default truss spacing of 600mm is assumed for each new Roof Perimeter and can be changed in the Properties panel for the selected area. Roof slope is specified later when we upload the end result to ClearCalcs.

Most drawings come with the roof area already drawn as a group block in the architectural, but we only want the external roof area, which needs to be a closed polyline. You may use whatever method you wish, but a couple of ways you could achieve this could be:

  • Use the Roof Perimeter tool to re-draw a new closed polyline over the top
  • EXPLODE the original roof outline, PEDIT and JOIN a new closed polyline using only the exterior lines before selecting the new object and running CC:ROOF to convert it.

N.B. Roof perimeters can be drawn on any level of a structure (you may have multiple) and will default to the currently active Plan Layer.

Relevant Commands

Roof Perimeter
Converts or draws a closed POLYLINE into a Roof Perimeter object

3. Draw or Convert All Studs/Columns

We suggest drawing or converting all of the studs and columns for a given Plan Layer after specifying the Roof Perimeter to make it easier to align all subsequently drawn Trusses and Beams on top of these supports. Columns are used to identify cantilevers and supports for trusses and beams. 

Columns are denoted on the CAD drawing as a POINT. Three possible methods for drawing or converting the columns/studs include:

  • Using the CC:COLUMN command to manually add each point
  • If you have an existing column/stud layer, you can quick select (QSELECT) the appropriate layer which will add all of the objects to the selection then run CC:COLUMN or press the Column button in the ribbon and a Column POINT will be created in the center of each selected object.
  • If you have an existing column/stud layer, you can isolate the layer and select all of the column objects before converting them with a single command.

Columns must be connected to a beam, wall, or truss (i.e. they cannot be on their own). You can select and move a column if needed, or delete if unnecessary.

Tip: You can change the point style (for example, making it look like a X) in your CAD program by typing PSTYLE in AutoCAD or PDMODE in BricsCAD and then specifying the new style you'd like.

Relevant Commands

Draws a POINT Column object. If you have an object currently selected, it will create a POINT in the centre of all currently selected objects which can be useful for batch creating Columns if you have existing objects denoting them in your architectural drawing.

4. Draw or Convert All Load Bearing Walls and Beams (Lintels and Bearers)

All Lintels, Bearers, and Load Bearing Walls must be drawn in or tagged in order for the plugin to accurately inherit loads and automatically size beams on upload into ClearCalcs. We recommend labelling each tagged Bearer and Lintel in the Properties panel so that they are easy to track once uploaded in ClearCalcs (for example, 1L1). Beams will adopt whatever Plan Layer is currently active when drawn in (for example, Ground

Use CC:BEARER, CC:LINTEL, and CC:WALL to draw in all beams and load bearing walls (ignore non load bearing walls). Load bearing walls can be drawn on their own CAD layer that can be hidden later if desired (ex. DEFPOINTS). N.B. If you are converting existing objects, they must be LINE objects, not POLYLINE.

The external wall must be one continuous line (otherwise your house would have a hole in it!), however internal load bearing walls and beams can be disconnected. If a line is disconnected, you must select the disconnected segment and tick "Allow Disconnect" in the properties panel.

For speed, we suggest that you start in one direction and go around so that the lines all attach correctly – try and avoid any diagonal/non straight beams and walls as this will likely cause errors.

To ensure accurate calculation, please draw beams center-to-center into studs (i.e. not clear span) and ensure the stud is connected.

After beams are drawn, you can add several adjustments in the properties panel including:
  • A label (Beam ID) - for example 1L1. This will be used to label the calculation when you upload to ClearCalcs.
  • Automatic label toggle - if on, will create a TEXT object with whatever Beam ID you have typed.
  • Allow Disconnect toggle - useful for interior beams that are disconnected on one or both ends.
  • No Roof Load toggle - tick when you do not wish the lintel or bearer to inherit any roof load or point loads from beams or trusses above.
  • Comments - will also be uploaded to ClearCalcs for later reference

Relevant Commands

Converts or draws a LINE into a Bearer object.

In the Properties panel you may specify an automatic label, add a comment, allow the beam to be disconnected (for example, if it is cantilevered, or interior), and toggle whether it should carry roof load.
Converts or draws a LINE into a Lintel object.In the Properties panel you may specify an automatic label, add a comment, allow the beam to be disconnected (for example, if it is cantilevered, or interior), and toggle whether it should carry roof load.
Converts or draws a LINE into a load bearing Wall object.If the Wall is not contiguous (i.e. not connected at the end - for example, an interior wall), you will need to toggle Allow Disconnect in the Properties panel.

5. Draw or Convert All Girder Trusses, Hip Trusses, and Valleys

The CalcsCAD plugin uses Girder and Hip Trusses, as well as any Valleys to infer rafter direction and the loads on each beam and lintel. You may either convert the existing objects if they're already on the architectural drawing, or you can draw them in using the CalcsCAD commands for each. Once they are drawn in, labels can optionally be added to each via the Properties panel. You can multi-select objects to convert them or change their properties all at once.

It is important to note that:

  • Girder Trusses and Hip Trusses require a minimum of two supports (either columns, beams, load bearing walls, or other Girder Trusses - a truss will automatically use another as a support if the other truss already has >=2 supports. Hip Trusses cannot support a Girder Truss however).
  • Hip Trusses must extend from (touch) a Roof Perimeter to a Girder Truss.
  • Valleys must extend from (touch) a roof perimeter to at least a load bearing wall or beam.
If you are converting the girder trusses included in the architectural drawings, it's important to ensure these are touching the beams, columns, or load bearing walls so that supports and point loads can be determined properly. This may require stretching the existing lines so they are long enough. If these lines are disconnected, you will get an error when validate.
Once you have finished drawing in all of these objects for a given Plan Layer, you can run 'Show Rafter Directions' and 'Show Tributary Areas' to validate your work (see below for more details on these commands). These commands will flag and zoom into any disconnected lines, as well as identify anything with unstable supports (i.e 1 or less supports). If you are unsure if you have missed anything, you may run 'Highlight Tagged' (CC:HIGHLIGHT) to quickly colour code everything with a ClearCalcs property. N.B. The Truss Roof commands will only work for the currently active Plan Layer so you may need to change the active layer depending on whether you'd like to check the ground floor or top level in a

Check Rafter Direction will zoom and auto select any truss area the plugin cannot automatically determine a direction for. -> Select the correct X or Y direction in the Properties panel using your judgement. You can multi select rafter areas that go in the same direction and change the property at once.

Once all directions are specified, Show Tributary Areas will display all the load width areas colour coded by the direction the load is travelling.

Relevant Commands

Hip Truss
Converts or draws a LINE into a Hip Truss object

Hip Trusses should have a minimum of two supports (i.e. load bearing wall and GT) and must touch both a Roof Perimeter and Girder Truss.
Converts or draws a LINE into a Valley object.
Girder Truss
Converts or draws a LINE into a Girder Truss object.

Girder Trusses should have a minimum of two supports (either columns, load bearing walls, other GTs, or beams).
Show Rafter Directions
Shows automatically predicted rafter/truss directions based on the Girders, Hips, and Valleys drawn in. Directions default to 'Auto' but can be overridden in the Properties panel and given a specific X or Y based on engineering judgement.

The command will flag all disconnected lines and issues that need to be resolved before directions can be displayed.

Areas with a red hatch denote areas the tool was unable to automatically determine - please set an X or Y direction in the Properties panel.
Show Tributary Areas
Displays load tributary areas colour coded by direction they fall (up, down, left, right). This is useful for confirming truss/rafter directions have been inferred correctly and loads are transferring as predicted.

The command will flag all disconnected lines and issues that need to be resolved before areas can be displayed.

6. Draw or Convert Joists (Multi-Storey Only)

In order to accurately determine floor loads, we need to draw in joists and orient them in the correct directions. Joists must have a minimum of two supports (either beams or load bearing walls). 

Generate Joists Automatically

Coming Soon - You will be able to draw a polyline surrounding each joist area and denote a joist direction and spacing in the properties panel.

Create Joists Manually

Drawing in joists one by one would be quite time consuming, so we suggest generating them for each joist area using the HATCH or ARRAY commands and then converting these into Joists.

To use the HATCH methodology:

a) Ensure you are in the correct Plan Layer (ex. Floor)

b) Create a closed POLYLINE tracing around the edge of the area which will have floor joists travelling in the same direction. Ensure the polyline snaps onto the wall and lintels in place else the floor joists will return errors of not being connected.

Once the entire area has been traced with one unbroken polyline, close the loop by typing ‘c’ and hitting enter.
The POLYLINE should then be selectable (note the dotted pink line in the example below):
c) Run the HATCH command to get the Hatch popup. Choose ‘user defined’ from the first dropdown menu. Set angle (0 for horizontal, 90 for vertical). Set spacing (in mm) for joist spacing - for example, 450 for 450mm. Click ‘Select Boundary Entities’ and the popup will disappear.
d) Click the POLYLINE we created earlier to denote the Joist area and hit enter - the joists should visually appear and the pop-up will reappear. Change the spacing or angle if it is incorrect, or click ok.
e) Delete or hide the POLYLINE outline if you wish
f) EXPLODE the hatched joist area (Click the block, type EXPLODE, hit enter).
g) Select all of the joists and convert to joists using the Joist button or CC:JOIST. (N.B. These must be Line objects first, you cannot convert the unexploded area).

Specify Floor Voids

Once you are done drafting the joists you can run CC:VALIDATEFLOOR to ensure everything has been drawn in correctly - any voids in the floor will show up in a red hatch and you will be alerted. To add a stair void, simply click the red hatched area, open the properties panel (CC:PROPS) and tick 'Floor Void'. The red hatch will be converted to a gray hatch denoting a floor void and the drawing will now pass checks.

Relevant Commands

Converts or draws a LINE into a Joist object.
Generate Joists
Draws a closed POLYLINE to denote a given joist area.

Joist direction and spacing can then be specified in the Properties panel when the given Joist area is selected.
Performs a check on all joist areas and flags any issues. Areas where the tool could not infer a joist direction or where joists are missing will be hatched red.

7. Add  Load Area Overrides

If required add any additional heavier load areas such as bathrooms or solar panels.

Relevant Commands:

Area Override
Converts or draws a closed POLYLINE into an Area Override object.

This tool may be used to override the default loads of a given area that may have heavier than default loads (for example, a bathroom or solar panel). The overridden loads can be specified in the Properties panel.

8. Export to ClearCalcs + Check and Resolve Errors (Connectivity, Overlap, Truss Directions etc.)

One you're done drawing, click the ‘Validate All’ button or CC:VALIDATE to double check everything is connected and not overlapping. The debug panel will say "Drawing is Valid" if no issues are found. Once you are happy with the drawing, run 'Export' (CC:EXPORT) to generate a .ccframe file ready for upload to ClearCalcs. This command will run Validate All prior to exporting and warn if there are any errors that need to be addressed first.

N.B. If you are working on a multi-storey structure you should ensure you have created a Plan Layer for each level tagged all objects to the appropriate Plan Layer they belong to.

Relevant Commands

Displays the Properties pop up panel which allows the properties of a given selected object to be viewed and changed. If an object is selected that has no ClearCalcs properties associated, the panel will be blank.
Highlight Tagged
Highlights purple all objects in a drawing that have been given ClearCalcs properties. This is useful for quickly determining if any areas of the house have been missed.
Hide Output
Hides any active command (for example, highlight tagged, show rafter directions, or show tributary areas).
Validate All
Checks entire document for connectivity and calculation errors and flags any issues that needs to be fixed. Problem areas should be automatically selected and zoomed to in the order they are resolved.
Clear Properties
Clears all ClearCalcs properties from the selected object/s. This is useful if you have mistakenly tagged an object you did not mean to.
Exports to a CCFRAME file for upload into ClearCalcs. This command will check to see the document is working first and flag any errors that need to be resolved before export is allowed. 

🎉 Congratulations! You have successfully drafted your first CalcsCAD project! 🎉

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