Ceiling hatch patterns in DWG and Revit are not the same

[Anonymous]

We aligned our dropped ceiling grids to match the alignment of walls, columns, corridors and other elements in the building, for each room. We also have several types of ceilings depending on the height, acoustic properties etc. so we assigned different colors to them.

Now we have to send the ceiling patterns to HVAC and Electrical as dwg. The engineers have to follow exactly our dropped ceiling grid lines to place their ventilation shafts, light fixtures etc.

The big problem is that, in several places, the alignment of the hatch pattern in dwg is not the same as in the Revit model. Sometimes they are not even rotated correctly. Also, all the hatches have the same color. 

Is there any known solution for this?  I cannot find anything relevant in the forum. Thank you!

[ennujozlagam]

@Anonymous hello, try to check it HERE and see if this can help. thanks

[Keith_Wilkinson]

Can you post a screen shot?  Hard to understand exactly what the problem is.

When you are referring to the 'hatch pattern' are you referring to the surface pattern of the ceiling family?

[Anonymous]

I think I understand what causes the problem. Have a look at the screenshots, see the difference between position 1 and 2. The alignment of the hatch pattern breaks when i start to move them in the DWG file.

I have one file for each ceiling plan. If they make only one file with all my ceiling plans side by side, or just move the drawing in another position they get the wrong alignment. 

I can't find any way to export the pattern as lines. So now i just export, it check it, and then explode it before i send to them. 

[Keith_Wilkinson]

Why are you moving the patterns in the DWG file?

[Anonymous]

I don't. They do! I just moved them so I could understand what causes the problem.

[Keith_Wilkinson]

So you are happy with your solution then?

[Anonymous]

Well no, I am not happy because I have to explode the hatch into lines and import it back into Revit. Then I have it as lines each time I export again. 

This way I make sure that no matter how other people work(no matter the software, the scale of the drawing or the point of origin) they will have the same grid. 

A good solution would be to have the ceiling as a 3D element similar to the curtain wall, but as far as I checked this is not possible. 

Another thing that I tried was to create the ceiling as a sloped glazed roof. The problem with this is the brick pattern that i want for the ceiling. If i make the pattern using a custom curtain panel, the panels situated on the edge are not aligned correctly. If i would have a simple square or rectangular grid i will use this method. It would be nice to be able to specify the grid pattern of the glazing as I do for the pattern of the ceiling, but so far i could not find a way to do it.

Maybe a macro could be useful to transform the pattern of the ceiling into some simple 3d extrusions, but i don't know the api at all..

Any other ideas are welcome! 

[Keith_Wilkinson]

Well the way the export is set up is a Revit Fill pattern will be automatically converted to an Autocad hatch pattern.  

I've just exported a view to DWG that contains 2 separate ceilings.  This comes through into Autocad as two separate hatched areas as I would expect and and they only change if I specifically tell them too... 

I'm guessing this isn't what you are seeing though - would part of the issue be that you are using Rhino to edit the DWG or am I just missing the point entirely?

[Anonymous]

My problem is that other software might read hatch patterns in a different way. Those engineers use MagiCAD.

Therefore I cannot trust hatch patterns for something as important as the ceiling. I verify using Rhino just because they complained back to me, otherwise I wouldn't have known.

I tested with AutoCad and the alignment is correct, still the colors assigned for each ceiling type under materials-graphics-surface pattern are missing. All the ceilings have the same color. Is there any other way to specify the color of the hatch pattern, by type, when exporting ?

Also, if I don't explode the hatches, AutoCad users will, dimensions don't work on the pattern of the hatch, they need lines.

Because of all these things, the sloped glazed roof is more reliable. But now, i have this brick pattern which i cannot draw with it. 

[Keith_Wilkinson]

That is a pickle.

I have say I'm sorry but I don't have any solutions for you.  If it was happening here I'd probably be providing a ceiling tile setting out drawing as a DWF/PDF and telling the engineers to make sure they don't change it.  If they have to they can draw it again if their software can't deal with the DWG correctly.  A DWF will carry across the colour and attribute data for the elements although whether they find that helpful is a different matter.

[Anonymous]

Now I have only 280 ceilings in the building, and only 5 types. So i can easily pick the ones that are different (mostly hygienic or with special acoustic properties) and recolor and explode them in Autocad before sending.

I would like to find some automatic solution before starting a larger project.

If anyone has any idea about how to do this with a macro please let me know. It would be an interesting exercise.  

Regards!

[ToanDN]

You can override the color for a ceiling either via element override or filter override.  They will export to different colors.

[Anonymous]

I tested with filters and it works! Thanks Toan!

I was expecting the hatch of the ceiling to behave like regular filled region when exported.

Now, the only thing that might improve the workflow is to export lines instead of hatches.

With lines I would make sure that everybody will get the same grid no matter the software they use, and that everybody will be able to work on the drawing directly without the need of exploding the hatch or redrawing the ceiling using a DWF/PDF as reference.