DWG files disappear

[stephanschneller]

Hi,

we are using Revit 2012 in the office and have a few problems with dwg files.

We are using dwg files in some section views as an underlay...now in a few projects they keep disappearing.

If I click roughly in the area where the dwg files is meant to be it gets selected...so it's there but it's not displayed properly.

The files are not hidden in view or/ switched of etc.

Any ideas why this is?

Regards,

Stephan

[sbrown]

Its set to background. select it and in the options bar change it to forground.

[stephanschneller]

Hi,

we've tried this but unfortunately changing this doesnt make a difference.


Regards,

Stephan

[cliff collins]

It could also be a "view depth" or clipping issue--go the the section mark and see how far the depth is set,
try adjusting it and see if the cad dwgs appear in the section.

Also, in a Plan view, see if you can find the cad dwgs in relationship to the bldg. footprint and where the section is.

cheers

[DaveP]

Try changing the View to Wireframe.
If the DWG shows up in Wireframe, that means it was hiding under something else - like a Floor. Although changing the DWG to Foreground should have taken care of that problem.

Does the DWG show up if you Zoom In (or Out)? If it shows up sometimes ans not others, I'd lay the blame on your graphics card. Try turning off Hardware Acceleration (big purple R... Options...Graphics). That screen in 2012 will also tell you if your drivers need updating.

[stephanschneller]

Thanks but unfortunately view depth, clipping and wireframe doesnt help either.

It seems that when you zoom out the dwg file appears in the correct location but when zoom in that's when the file disappears....?

[DaveP]

That's definitely Graphics Card.
Although, I just had an odd one last week where the DWG disappeared if part out it was outside the Crop Region. Never did figure that one out.

[stephanschneller]

Hi,

I've now checked varies models on three different machines (with completely different specs) and now change so Im not sure whether its the graphic card?

I have than selected a few elements from that section, created a group, saved and opened as a new project....no problem there!

I just wonder if something is wrong with the original project file?

Also, Im a bit confused that no-one else seem to have come across this problem?

[stephanschneller]

Hi,

we found two workarounds:

1. Import the dwg file into a 'detail-component' family and than load into project. (not very good as you cant really modify the dwg within the project)

2. Link the dwg into a plan view, copy and than simply paste into the section view....that seems to work perfect.

Regards,

Stephan

[scowsert]

Thanks for the work around. I too was having a cad linked in file disappear in 2012 as I zoomed in. I wasn't able to cut and paste from a plan view to an elevation but the detail family trick worked great. Man talk about a wasted 2 hours.

I could zoom out and see it. Zoom in and it just poof gone.

[Wes Macaulay]

We've had this issue, too. Has anyone submitted a support request on this issue?

[Revitaoist]

I have had several issues with the so called interoperability of CAD & Revit. The best solution I found is to explode the dwg in a family, convert it to revit lines, copyclip it to a new family, then make revit linetypes for all the layers. Everything is native revit and no more lost links, or imported garbage.

[Deanso]

I have been struggling with this problem through many projects. I mainly have this issue when using .dwg as backgrounds in sections in order to set up work planes and coordinate between my model and an architect's drawings that are in .dwg format. What I have found (this is in Revit Structure) is that whether or not the .dwg disappears is dependent on the section orientation.

I found that the .dwg file does not disappear if I flip the section around (as in hitting the flip button on the section mark when viewed in plan). To get around this I have been mirroring the .dwg files so they still correspond to my section orientation.

Anyway I don't understand why this happens but it works for me.

Cheers

[cborgen]

I've been having this issue with detail views, and saw the suggestion on another thread that the Far Clipping might be to blame. Changed the detail view Far Clip Settings to "Independent", and Far Clipping to "No Clip" and it appears to be resolved. Worth noting that I was also experiencing the behavior of zooming out to see it, then disappearing upon zooming in...certainly seemed like a video card issue initially.

[brethomp]

We have had this issue with several files as well, and have reported it to Subscription Support. They confirmed it is a bug and has been fixed in 2013. For us, the work-around was to change the far clip depth of the view, but we never tried the Detail Component trick, that sounds like it would work.

[bulletproofdesign]

I have found that some (seems random) dwg's disapper when they aren't contained completely in the screen. This is not cause by cropping regions, it is the screen? I can zoom out and pan, as soon as the dwg hits the edge of the screen, it disappears.... Changing View depth does stop this behaviour, and I tested without hardware accelleration, and it persists...

Must be time for a support request...

[MikeJarosz]

Here's my 2 cents:

Are you paying attention to units? Some disciplines in Acad want to see decimals of a foot, which Acad has never been able to do efficiently. They draw in decimal inches and pretend the numbers represent feet. The result is a file that is 1/12 true size. A similar workaround is employed for metric. The data has to be scaled to get it into true architectural units, which moves it away from the origin point by the scale factor used. Ughh.

When importing a dwg file into Revit, Revitis supposed to correct for this anamoly, but the correction can be misused, especially by users who don't understand the problem. If the data is very far from the origin, a condition Revit hates, it may have been scaled 12 times an already big number. If your data can be seen at all, it will be a single pixel way out in space.

In acad, set your units to feet and inches, and measure a doorway or some other object. If the distance is reasonable you're OK. If a doorway is 90 feet, you probably have an engineering file that used inches as if they were feet. Also check the origin. Ifthe data is far out, move everything to 0,0,0. Bring it into Revit and fix coordinates there.

[mike99]

When I worked in 3dsmax, if the imported DWG files have one or sevral points, or sth like that, it will ont be found in the viewport. Sometime, the DWG file has a point far away in a vertical direction. So that, if delete the far away part, the file then works well. I am not sure if this is useful for your files.

[MikeJarosz]

When I worked in 3dsmax, if the imported DWG files have one or sevral points, or sth like that, it will ont be found in the viewport. Sometime, the DWG file has a point far away in a vertical direction. So that, if delete the far away part, the file then works well. I am not sure if this is useful for your files.

Turn your Acad view on edge using front or side views. This will expose the z axis, then zoom extents. If you have z-data way out, this should show it. It may also expose that the drawing is not drawn on a flat 2D surface, an error that occurs often in Acad because users are thinking in 2D and are unaware that some of their data has escaped into the alien z-realm. Always use extmax and extmin to see if you have space data. Unfortunately, I have never seen a good flatten script.

I once had a file with a z-extent of 32,000 feet. Mount Everest is only 29,000 feet!

[MikeJarosz]

After posting the previous response, a thought occured to me. It is a well known fact that Revit does not like a building to be far away from the origin, but the discussions I have seen focus on x and y axis. As I noted in the previous post, it is very easy in Acad to get a humongous z-extent and not even know it. The 32,000 foot example I noted is just over six miles! That is triple the two mile limit recommended by the factory.

Is the two mile recommendation limited to x and y, or could the z axis cause problems too? David Conant, are you listening?

[mike99]

Turn your Acad view on edge using front or side views. This will expose the z axis, then zoom extents. If you have z-data way out, this should show it. It may also expose that the drawing is not drawn on a flat 2D surface, an error that occurs often in Acad because users are thinking in 2D and are unaware that some of their data has escaped into the alien z-realm. Always use extmax and extmin to see if you have space data. Unfortunately, I have never seen a good flatten script.

I once had a file with a z-extent of 32,000 feet. Mount Everest is only 29,000 feet!

After import the DWG file into 3ds max, we make all the shapes and others to one group, then make a Z-scale to it,value=0, and then it is a flat dwg. I just need the dwg file to be a backgroud to set up the model to render, so that is a simple way.

[MikeJarosz]

After import the DWG file into 3ds max, we make all the shapes and others to one group, then make a Z-scale to it,value=0, and then it is a flat dwg. I just need the dwg file to be a backgroud to set up the model to render, so that is a simple way.

I'm not a 3D max user, so I will believe you when you say 3D max can flatten a file. My statement applies only to Acad. Years ago I used a CAD system that allowed the x,y and z coordinates of a point to be edited. A single command could make all z values = zero (or any other value), including inside block definitions. I used to translate dwg drawings into that program to flatten them, but over time the dwg file format changed and the older system could no longer read the newer dwg formats.

If 3D max files can be sent back to Acad after flattening, you have discovered a valuable process that more people should be aware of.

[bulletproofdesign]

2. Link the dwg into a plan view, copy and than simply paste into the section view....that seems to work perfect.
This is odd behaviour and solves my problem.
When I link directly into a section "current view only" as soon as the dwg touches the edge of the viewport, poof, gone.
Copy then paste to the same view, same behaviour for both instances.
Paste into a plan view, then cut/copy and paste back into the same section, works perfectly.

So probably a code issue not a graphics card issue...

At least this work around seems to be working for now...