maximum image size

I would question the value of creating a 300dpi image meant for a final output size of 8'x4'. 

Large images like that are usually viewed from several feet away and a such seldom benefit from the added resolution. To the contrary, they take longer to render and print, and often cause problems when sending them to the printer/plotter.

We normally use a maximum of 150 dpi for posters. This allows us to create displays which maintain smooth, readable text and smooth line work. If the final image doesn't have any text or line work, where aliasing of the edges is most noticable, you could probably reduce the dpi to something like 100dpi or lower and still achieve acceptable results.

Just because a printer or plotter is capable of 300, 600, or even 1200 dpi output doesn't mean they require(/or benefit from) that resolution in the image being printed. The determining factor for resolution of the image your are rendering in MicroStation should be, "What is the lowest resolution that produces acceptable results at the desired viewing distance?" You can try a small 1'x1' section of the image rendered at various dpi (72, 100, 150, 300, etc...), and plot each out at 1'x1' and compare the results.

Use the lowest resolution that looks good.

HTH,
-Ron

anyway, thanks for the reply and the option. i was thinking of doing that if i couldn't get this to work.

Matthew,

I'd suggest to render as big image as your RAM allows you (guess you're on 64bit system) and then use Photoshop to enlarge the image - I had quite good results using Genuine FractalsPhotoShop plugin ... check their page >

http://www.ononesoftware.com/detail.php?prodLine_id=7

HTH

p.

FWIW:
Here's a link to an excellent explanation of DPI, PPI, image resolution and the confusion many people have about it.
  The Myth of DPI 

Also from the same site:
   What Magazines / Printers Really Want  
  The Arithmetic of DPI 
(You might want to send these links to your client.)

HTH,
Ron

On a previous project and an older version of luxology we had the same issue of (then) too large renders crashing.

The workaround that got us through was to set up and save the view as required, rendering a small sample image to get the "adapt to brightness" correct and saving those settings. Dragging the border of the view port halfway (allowing for some overlap), rendering at full resolution then recalling the view and dragging the opposite border to halfway, and rendering. Finally using photoshop to stitch the two halves together.

 The few images we did this way were very nearly pixle perfect at the overlap...

 Hope this helps

On a previous project and an older version of luxology we had the same issue of (then) too large renders crashing.

The workaround that got us through was to set up and save the view as required, rendering a small sample image to get the "adapt to brightness" correct and saving those settings. Dragging the border of the view port halfway (allowing for some overlap), rendering at full resolution then recalling the view and dragging the opposite border to halfway, and rendering. Finally using photoshop to stitch the two halves together.

 The few images we did this way were very nearly pixle perfect at the overlap...

 Hope this helps