In this session, I’ll show you how to use “Grid” tool to place grid lines for laying out. Before starting the construction, we need to lay out first, in order to accurately place the construction elements on the site. Similarly, before we build a house in the virtual environment like Revit, we also have to lay out first for accurately positioning columns. In Revit, we use Grid tool to achieve the same purpose as layout. If we already have grids in CAD files, we can import them into Revit. They can serve as reference maps to help us position all the grid lines. But we need to be aware that the imported CAD grids are block files. Because the lines of CAD grids are just geometrical entities, not grid line elements in Revit, their properties cannot be changed. But the grids in the CAD files still help a lot, we can take the CAD lines for reference and place grid line elements along them. Now, let us import the CAD file of architectural plan view. First, open B1 view in the branch of “Views” and “Floor Plans” in the Project Browser. Then, in the “Insert” tab, select the “Import CAD” tool. You can see a window called “Import CAD Formats” pops up, and we should select the dwg file we want to import. Before opening the file, we need to check the import setting in the bottom half of the window first. Check the checkbox called “Current View Only” and this CAD file will not be displayed in other views but only current view. Select “Centimeter” option from the “Import Unit” dropdown menu because we used centimeter when exporting the CAD files. Select “Auto – Origin to Origin” from the “Positioning” drop-down menu. This helps us align the coordinate system of imported CAD with that of Revit project. After these are done, we can click on “Open” now. After importing the CAD file, we should check whether the unit is correct. Let’s take the column in the left top corner as an example. The section of the column is supposed to be 40 by 40 cm. We can use the Measure tool to check if the size is really the case. Now, Click on the “Modify” tab and select “Yellow Ruler” icon on the “Measure” panel. Click on the two parallel edges of the column in sequence and we can get the distance between them. By checking if the distance we’ve measured is the same as that in the CAD file, we can ensure that the CAD file has been imported correctly and accurately. Now, we can start to create the grid lines in Revit with the help of the CAD grids. First, click on the “Architecture” tab and select “Grid” icon on the “Datum” panel. Select “Pick Lines” on the “Draw” panel. By clicking on the CAD grid lines, we create the grid line elements in Revit at the same time. Let us start from the left to the right, click on every vertical CAD grid line in sequence. Now, we can see that the grid line elements created from Revit overlap the grid lines on CAD. Then we drag down the endpoint of one of the grid line elements to get all grid lines extended so they can be seen clearly. The grid line elements are now individual elements in Revit so we are able to change their properties if needed. Then, we follow the same procedure to create horizontal grid lines from the bottom to the top. We can click on the head of grid lines to change their names. Name is one of the properties of grid line element. OK, we have finished placing all the grid line elements for the example. You can see that the names for the vertical grid lines are one, two, three, four from left to right and, for the horizontal grid lines, they are D, C, B, A from top to bottom.
