Disappearing Bitmap images

[jmarkey]

I have been consistently having a problem that CA Tech support has been unable to figure out. My firm sometimes receives hand drawn surveys instead of CAD files. Typically, I will scan the hand drawn survey, convert it to a Bitmap file and then import it to CA. The idea being to draw the site plan modifications over the bitmap image without redrawing the entire survey. The problem is that after drawing some CAD and text on the image it disappears leaving only the border. Sometimes closing CA and rebooting brings the image back. Then some files that are present in plan do not show up in layout. I even have one image that will not show in the layout at zoom extents but can be seen when I zoom in!!??! It also refuses to print. This is not an isolated occurance, its happened 5 or six times with different files. When I import the same bitmap images into AutoCAD 2000 they behave fine. Any help would be appreciated.

John

[David J. Potter]

Wish I had some "Sagely" advice for you (I don't think I do). I use "bit maps", same as you but I do convert them to .jpegs instead of .bmps. I then use the imported .jpeg to trace-create a "Terrain" using "Elevation" lines-splines-features tools. I have never had these types of lines disappear on their own.

Are you using 2-D CAD lines to represent just a 2-D terrain map? You should not have lines disapearing, what ever the type, certainly.

You might also check your Screen refresh rate/resolution at different settings to see if these changes help your display problems as you have discribed.

What video board are you currently using?

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David J. Potter
Chief Architect™Consultant, Beta Tester, Designer
1801 Wells Branch Parkway #2013
Austin, Texas 78728
dpotter1@austin.rr.com
512-251-3982
305-425-5794 FAX http://members.spree.com/djpotter

[Larry Kumpost]

John:

First, I'm not sure why you would be having problems with the bmp image.

Have you looked into any raster to vector conversion programs. They would convert your scanned image into a vector CAD drawing.

The best way is to contact the surveyor and see if they have a CAD file to send, but I assume that your talking about the times when it is not available.

I remember down-loading a free conversion program several months ago but never had a reason to use it. I'll take a look for it and let you know.

Larry

[marty]

How big is the BMP file and how much RAM do you have? You may be overloading your resources.

[jmarkey]

David, Larry, Marty,

Thanks for the replies. I'm not using CAD lines to represent contours, but rather things like handicapped routes-parking, areas of remodeling and such. No terrain modeling. It is not the added CAD lines and text that disappear, it is the bitmap image. CA CAD, text and the image border remain visible. I'm using an NVIDIA TNT2 card with 64 MB on the card. I downloaded and installed the latest driver for it. This seemed to stabilize some of the smaller images, but not the biggest one (of course that's the one with the looming deadline). I would definitely be interested in raster conversion software if you can remember where you downloaded it. I'm using 384 MB of ram so I don't think that's the problem. Bitmap image is large though-16.5 MB. Funniest part of all this is that ACAD 2000 handles and plots the image fine. Thanks for your help, don't know if the additional info here will help-I'm at a loss.

John

[David J. Potter]

That is a large bit map, it's size may be the problem. Try converting it to a .png or .jpeg and see if it remains for you, once converted.

------------------
David J. Potter
Chief Architect™Consultant, Beta Tester, Designer
1801 Wells Branch Parkway #2013
Austin, Texas 78728
dpotter1@austin.rr.com
512-251-3982
305-425-5794 FAX http://members.spree.com/djpotter

[Larry Kumpost]

John:

Here is the link to the free conversion program:
http://sourceforge.net/projects/autotrace/

I have not tried it yet. I haven't had anything to convert. But I'm a little slow right now so perhaps I'll scan a topo and see what it can do.

Larry

Or perhaps I will see if I can get it working first.

[This message has been edited by Larry Kumpost (edited 10 May 2001).]

[jmarkey]

Thanks to all of you who tried to help. I managed to find a solution on my own. It became obvious that the imported bitmap image was simply too large for CA to handle.
The bitmap in question was a scan of a full D size (24" x 36") survey. I took the original scan in Photoshop and reduced it too about 2" X 3" (5MB down to 120KB)then imported it to CA. Then I just resized it to 1:20 scale in a plan file. The image came into CA @ 120KB and stayed that way after resizing. No more disappearing or plotting problems. Seems like a simple solution after you figure it out. Had me confounded for days. Hope this may help some of you in the future. Thanks again.

John

[Ted Terrenzio]

Disappearing Bitmap images