Banded photo rendering again

[Scott Bulmer]

I apologize if this is not the correct forum for this but here goes; I have tried everything I know to fix this problem (see attached banded image) and now need professional help determining if it is the graphics card. We have the latest driver for the card & I've set the hardware acceleration off in both the driver settings as well as Image Settings in AC. We have also messed around with the Virtual Memory settings but nothing seems to work. The model is only 16MB. The banded images do not happen the first rendering attempt after opening AC, but every time after that. The Photo Rendered image is fine every time using the built-in sun, however renders banded with the Sun & Sky objects, even set with low amounts of light sources. Although our card should be good, I will get a new card if required. Any other thoughts are sincerely appreciated as my back is against the wall. Our workaround for this is to restart AC9 each time we want to generate a LW rendering. Restarting AC resets something, who knows what.
Thanks,
Scott

[Scott Bulmer]

Further information;

Using WinXP and a 16MB PLN, we are able to render in LW up to a point. Using the marquee for portions of the building, renderings are OK. But through experimentation, continuing to enlarge the marquee area eventually causes the resulting image to break down into horizontal banding. Further, if higher quality image selections are made, the banding becomes worse.

On a positive note however, we have been able to complete renderings from the same file using the LW engine on an old Power PC G4 867 MHz w/ 640 MB ram. The only downside is that it takes approximately 40 minutes, but comes through. Upgrading the ram would most likely help speed things up, I think or hope. Note: we can get about 90% of the same model with XP in about two minutes. More than 90% gets banding.

So the end result of all this is that, I guess there is some type of memory limitation to WinXP that OS X does not have. Maybe it’s the difference between 32 and 64 bit processing (which I don’t pretend to understand), but have been told is the main difference between the two architectures. Perhaps someone knowledgeable on this topic could share some “Light.” That’s all I have for now as I believe the problem's solved.

[Dwight]

You seem to be the only guy in the universe with this problem.

There would be plenty of whining if a common operating system failed to allow a render.

Can it really be a software issue?

[Anonymous]

Maybe not,

I have had similar experiences but the whole render disappears in XP while the mac continues on it's merry way, only in LW though. If I use the internal rendering engine it will render on XP but again it takes forever.

I do know that a 'problem/error' in the file can create blank renders but seems strange that the same file can produce 2 different results on 2 different systems, maybe that's just it though!

One product, 2 systems, many rendering solutions!

is it is in HK:

One Country, 2 government systems, many dining choices!

[Djordje]

Dwight wrote:
You seem to be the only guy in the universe with this problem.

Nope, the same was reported by Kim some time ago ...

http://archicad-talk.graphisoft.com/viewtopic.php?p=48825#48825

... so this is not an isolated case.

[Dwight]

Two, then. (avoiding obvious gender joke)

I can see that I am no match for your archive skills.

What is common between their systems?

[Gerald Hoffman]

I have also had this happen recently on a big model. When I took off the Roof Tiles applied with the CadImage Accessories Add-on I was able to render the image.

Are you using roof tiles by any chance? I don't know if the add-on is the problem or just the large number of polygons of the roof tiles throwing the proverbial spanner into the works.

[Scott Bulmer]

Gerald wrote:

Are you using roof tiles by any chance?

When this first became an issue several months ago, we were using the 'Roof Surfacer' that came with AC. After eliminating the RS objects, the model began to render fine again and we thought that was the end of it. Now however, the model has grown a little and the problem's back as I've described below. I guess for XP users, don't place too many curving shapes or objects with detail in your model as they will chew up memory as it relates to LW when using the Sun/Sky objects. OS X users, party on.

Scott

[Dwight]

Just out of curiosity, now that we are getting closer to this being a RAMulon issue.....

Post your sun object and sky object settings - you can easily overdo it with these objects.....

[Scott Bulmer]

Thanks Dwight. For your perusal:

Over sun sources = 6
DA = 45
Shadows = on

Under sun sources = 4
DA = 45
Shadows = off

Sky object
Lat = 3
Lon = 6
Shadow = on
Soft = off
S Quality = 2