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Joined: Fri, Jul 17, 2015
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Working in Revit LT 2014.
Our office is trying to figure out how to export from Revit to AutoCAD (also 2014) and have a DWG that will print correctly without needing to modify graphics in AutoCAD. The best workflow I can figure out is to export from Revit using "Export category properties BYLAYER and overrides BYENTITY" and then plot from AutoCAD using a ctb file that prints using the object's lineweight setting rather than color. Theoretically, with this workflow I should be able to export a sheet to AutoCAD, plot it, and have it look exactly the same as a plot directly from Revit. (Right?)
I did that, and they are not the same (see two attachments). The differences I notice immediately are not lineweights, but color of fills: the walls, scale bar, and filled regions in title block are all darker in the AutoCAD version than they are in the version exported directly from Revit. Why would the graphic properties of those objects not be translated to AutoCAD properly?
Also, if you know a better way to approach this workflow, I'd love to hear about it!
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Getting an exact match is almost impossible. I would not do what you propose.
Several factors here. First and foremost is that Revit's lineweights are dynamic and driven by view scale. That in itself will give you problems. Run this very simple test:
- Floor plan view - short wall that has multiple layers with one being brick
- Set the view to fine 1/8" scale
- Copy the view and set to 1/4" scale
- Copy the view and set to 1/2" scale
- Copy the view and set to 1" scale
- Place all views in sequence on a blank sheet
- Export normal bylayer overrides by entity.
- Now inspect the lineweights
For me in Revit, my cut lineweight for walls is 7. A 7 @ 1/8" scale is .026" (0.6604) In CAD, that line says .53mm
In 1" view, that line in Revit is .0276" (0.70104 mm) In CAD that line says 7mm
Hatch patterns in Revit are typically pen 1 - .0030" in CAD they become .09mm (0.00354331")
So there are conversion problems here.
ALSO _ USE THE PCP FILE THAT REVIT PROVIDES instead of the ctb file. It will get you closer.
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I understand Revit's lineweights being dynamic could be a problem, but would it be a problem if we stick to the same scale that is exported? For example, we export a sheet at 1/8" scale, make some changes in CAD, and ultimately print a drawing that is still at 1/8"?
Anyway, the lineweights themselves are working okay for me- they aren't perfect, but the relationships between lineweights are matching our intent. What is not matching our intent is the color of fills, as I mentioned.
Plotting with a ctb created from the PCP file isn't working, either. From looking at the ctb file, it looks like Revit automatically generates lineweights for this file that match the settings in the Revit drawings, but there isn't a % screening for any of the colors in the ctb file, so everything prints black. This method is actually a bit worse than printing with the object type properties.
I gather that it would just be better to avoid this workflow of exporting from Revit to AutoCAD and then printing from CAD, but the people who make decisions about our workflow want to be able to do it this way.
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Joined: Fri, Jul 5, 2013
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Regarding precision and consistency in linetypes. Those interested in ISO linetypes that are correct in all scales and thicknesses, should have a look in this webpage:
http://www.archigrafix.com/technical-lines-iso-128-20.html
-----------------------------------
Marc Faber
BIM Solutions Developer
goto.archi | Oslo, Norway
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OP did you find a way to do this? Im facing the exact same problem and have created several ctb files to try to match the revit exports but with no success. This happens specially with the elevations. Maybe will have to create separate ctb files for plans and elevations. Using the pcp is fruitless and the people in charge refuse to plot from PDF.
Please tell me you found a workaround, im desperate...
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