Site Survey CAD Import Distorted

[Anonymous]

Hello,

I recieved a DWG file from a civil engineer so I could update my Revit model site. The CAD file looks perfectly fine in Autocad. Lines that are supposed to be parallel and perpendicular look perfectly fine. But when I link to my model, lines seem distorted in the X axis. It won't let me align or dimension between CAD and Revit elements because it doesn't read these lines as parallel. I've tried everything I can think of in Autocad. I'm not sure the original software used to create the site survey before they converted to CAD. Not sure what else to add.........

[barthbradley]

sounds like the CAD is far away from the Internal Origin in Revit. 

[Anonymous]

Is there any way to fix this?

[ennujozlagam]

have you try to set your autocad file VIEWRES to 20000 and untick correct lines that are slightly off axis and check your ddunits in autocad and revit if they are the same and see if helps. thanks

[barthbradley]

First, let's verify. Is the CAD far away from the IO? 

[Anonymous]

It seems to be pretty far away.

[barthbradley]

Okay, it sounds like I hit the nail on the head.  You simply need to unpin and move the CAD to the right position/orientation relative to your Revit model.  Do you have any known/fixed coordinates you can work with to achieve this, or are you just eyeballing placement?  

[Anonymous]

I have a plan view CAD export from my model I used the origin from that to move the CAD more in alignment. Re imported trying both with the "correct lines etc" checked and unchecked. The problem persists. 

[barthbradley]

---

@Anonymous wrote:

I have a plan view CAD export from my model I used the origin from that to move the CAD more in alignment. Re imported trying both with the "correct lines etc" checked and unchecked. The problem persists. 

---

I have no idea what this means.  Bottom line is that Revit has a distance limit. If you have elements placed more than 10 miles from the Internal Origin, you can experience issues such as you are describing.  The remedy is to move those element closer to the IO.  

Here's some literature on the subject:

https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/CloudHelp/cloudhelp/2018/ENU/Revit-Model/files/GUID-3F79BF5A-F051-49F3-951E-D3E86F51BECC-htm.html

[_Vijay]

Can you show some images?

[Anonymous]

I tried matching the origin point in the CAD file base don the Revit origin point. When you say move closer. I have my CAD directly over my model so I can trace, align, etc from the CAD overlay. So I'm not following you. These 2 elements are as close as one can get them.

[Anonymous]

The cyan lines look perfectly stright in CAD and read as either 0, 90, 270 degrees etc in CAD. When linking to Revit the come in angled. So if I try tracing over them in Revit. They become distorted like that. The black lines are my Revit in place family.

[barthbradley]

---

@Anonymous wrote:

I tried matching the origin point in the CAD file base don the Revit origin point. When you say move closer. I have my CAD directly over my model so I can trace, align, etc from the CAD overlay. So I'm not following you. These 2 elements are as close as one can get them.

---

Go to a 3D view and Zoom to Fit, and then, under VGOs, check Site: Internal Origin, Site: Project Base Point and Site: Survey Point. Now examine the view and tell me where the CAD is located in relationship to these 3 points.  

[barthbradley]

---

@Anonymous wrote:

The cyan lines look perfectly stright in CAD and read as either 0, 90, 270 degrees etc in CAD. When linking to Revit the come in angled. So if I try tracing over them in Revit. They become distorted like that. The black lines are my Revit in place family.

---

Sounds like you are tracing on the wrong Workplane. That is, the Workplane you are tracing on is not parallel to the Workplane of the imported CAD linework.  

[Anonymous]

591 ft.

[barthbradley]

---

@Anonymous wrote:

591 ft.

---

That's nothing. 

Can you post any illustrations showing what you are talking about?   

[Anonymous]

Never seen that happen before and I've linked CAD files hundreds of times. Is there a way to confirm/fix this?

[barthbradley]

---

@Anonymous wrote:

Never seen that happen before and I've linked CAD files hundreds of times. Is there a way to confirm/fix this?

---

Great!  Then we should be able to figure this out.  I just need some help understanding the issue. Pictures would help immensely.  

[Anonymous]

First image (blue lines) is the CAD. Second image (cyan lines) are what the blue lines look like when linked.

[ToanDN]

Open the CAD file, thaw all layers, zoom extent. What do you see?