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Small black square "dots" on high quality renderings
Hello, I started using SweetHome3D a few days ago, and am having a blast designing and rendering homes with my wife. I've encountered a rendering problem though... Background: we're using SH3D on 2 computers, a modern desktop and an older laptop. Both are running Ubuntu Linux, and version 3.3 of SH3D. The problem is that when rendering a photo with maximum quality, in many very "shiny" or luminous places, we get small black squares. If we render the same image on the two different computers, the small squares are in the same places. They're really small, maybe 2-3 pixels on a side, but they're really annoying. They happen mostly on/near lights, or on shiny objects where they're reflecting some bright light. If there's a way to post pictures, I have two large, high-quality renderings that show the problem - and it happens in 99% of the renderings, so it's really annoying. It can't be a graphic driver thing because 1) the two computers have totally different brands and families of video card; 2) I think at the highest qualities, the image is rendered by the CPU alone...
Netherlands
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Re: Small black square "dots" on high quality renderings
Cristian,
You may want to read this post for info on how to share pictures and or files.
As to your rendering problems: - The forum has 18 posts/threads on "white spots" and 10 on "black spots". They may offer some insight in the problem. - Q1 and Q2 rendering depends on hardware, and your video card may influence results. Q3 and Q4 rendering depends on software and should produce identical results, even between different computers. - Ubuntu is fine, I'm using it myself with no more (or less) problems than people using another OS. - Q3 uses a different rendering routine than Q4, so apart from a difference in the quality, there may be difference in the general appearance. Hence black spots in Q4 and not in Q3. - You may want to experiment with the settings of the afflicted (furniture) models. Changing between Unchanged, Matt and Shiny may (or may not) solve the problem. - You may want to use Q3 (which doesn't have the spots) and make an extra large rendering, which you then reduce in size to obtain the same quality as a Q4 rendering. - You could share your design, so we could have a look at it and see if we can reproduce, isolate, or solve the problem, and/or offer a workaround.
Hans
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Hans
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Re: Small black square "dots" on high quality renderings
Hi Hans,
You may want to read this post for info on how to share pictures and or files.
Thank you, I did that, attaching the files now... two pictures showing the problem and the project file (large!)
- The forum has 18 posts/threads on "white spots" and 10 on "black spots". They may offer some insight in the problem.
I'm sorry if there were already other answers... I tried a search, but I think all I found was a suggestion to move the objects around a bit, which didn't work for me. This appears to be like a non-graceful overflow of some sort when there are points too bright... But then, in one of the photos you can see the dots also in the mirror, so who knows.
- Q1 and Q2 rendering depends on hardware, and your video card may influence results. Q3 and Q4 rendering depends on software and should produce identical results, even between different computers.
Indeed... That's why I ruled out driver problems, and I did point out that renderings on two different machines gave the black spots in the same places!
- You may want to experiment with the settings of the afflicted (furniture) models. Changing between Unchanged, Matt and Shiny may (or may not) solve the problem.
Yes, changing things to matte does prevent objects from getting dots; but 1) some objects I want to be shiny; 2) lights often have the spots, and they don't go away just setting the light to matte. That too makes me think the program doesn't handle well what happens when it renders a very bright point.
- You may want to use Q3 (which doesn't have the spots) and make an extra large rendering, which you then reduce in size to obtain the same quality as a Q4 rendering.
Would that really be the same quality? Same shadows and lighting? And how much bigger should it be, would 2x on both directions be ok, to be then resized with a cubic resize?
- You could share your design, so we could have a look at it and see if we can reproduce, isolate, or solve the problem, and/or offer a workaround.
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Re: Small black square "dots" on high quality renderings
In the first image you can see black dots in the fridge and the kitchen sink, and (less visible) on the lights above the green painting and on the rail lights above the kitchen. In the second image they're on the mirror, on the window, and on the photos on a shelf; and, less visible, on the vase over the window, on the apples on the table, and on the vase near the apples.
Netherlands
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Re: Small black square "dots" on high quality renderings
Cristian,
A large render would only be useful if you plan to print your image. Your screen can't display all those pixels. Your printer, however, has a much higher resolution.
Example: - a 10x10 inch image on your screen can show a maximum of 720x720 (or sometimes 960x960) pixels. - a 10x10 inch image on your printer can show easily 3000x3000 pixels when printed at 300 dpi.
So, if there are jagged edges in the screen image, they would (almost) disappear when printed.
Also, since version 3.0 the quality difference between Q3 and Q4 is much smaller than it was in earlier versions. Personally, I don't use Q4 anymore, because the slightly higher quality doesn't justify the much longer render time.
Hans
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Hans
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Re: Small black square "dots" on high quality renderings
Two more things: 1) I tried rendering a larger Q3 picture and rescaling it... No black spots, but in Q3 there are no light reflections on shiny objects. And those really add to the realism, so I'd like to not give them up. 2) I also tried the old "advanced rendering" plugin, and it doesn't have the spots; however, it doesn't take into account the power of the lights. It either has them all on at 100% (not good) or all off (black picture, unusable). So if I want to have a good rendering with light levels as I set them I have to use the built-in renderer; and if I want to see the reflections on objects I have to use Q4. I might resort to "editing away" the black spots in Gimp, but that's not optimal IMO...
Netherlands
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Re: Small black square "dots" on high quality renderings
Cristian,
The reason I made the reference to earlier posts on black and white spots was to provide you with some background info. The spots-problem dates from v2.6 and the AdvancedRender plug-in. SH3D uses an external render engine, Sunflow, and there has been cooperation with the programmer(s) of that renderer to solve some problems. As you can see on their website, excellent results are possible.
Before deciding how to incorporate the AdvRender plug-in into SH3D, a lot of testing has been done with different algorithms, settings, etc. Puybaret (the developer and programmer of SH3D) and db4tech (who made a major contribution to the development of the AdvRend plug-in) have made a trade-off between render time and image quality. I can easily imagine a Q5 setting that would produce the bestest and sharpest and perfectest images possible. The price? Render times of a week on the average computer.
SH3D isn't intended to produce professional quality designs or images. Nevertheless, if you know how to use the program, amazingly good results are possible.
As to a solution of your black spots problem: there is no easy solution. Trial and error may be the best option: change models, time of day, viewing angle, light level, etc.
Some general advice: As you seem to have discovered already, making models invisible reduces render time. You could make more models invisible, especially trees. If you use textures, don't make them larger (if possible) than 512x512, and definitely not larger than 1024x1024 pixels. Be careful with imported DAE models from Google Sketchup Warehouse. Read the multi-level tutorial for a different approach to designing the loft.
Hans
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Hans
Re: Small black square "dots" on high quality renderings
I am building two private homes for myself and thus find sweethome3d just perfect to visualize the homes upfront.
I need to say that I do suffer from exactly the same black pixel problems as Christian has in rendering mode 4. Especially for simulating time of day sunlight and night artificial light situations the black pixels are just annoying and there is no way around it for non trivial homes. With non-trivial I do mean that I am relying on additional .dae imports from sketchup warehouse while I do know to be careful with them.
I do agree with you Hans, that the faster rendering of mode 3 is quite helpful - especially for batch rendering - , but as Christian mentioned mode 4 is still needed. and I am fine if for 50% more rendering time mode 4 gets just rid of these black pixels that occur in pretty much every mode 4 rendering which currently is almost useless for me.
Thanks, Bernd
p.s. I want to thank Emmanual for version 4 of sh3d, all capabilities especially color management and batch rendering are just amazing and it helped me a ton right away. alone these improvements are definitely worth the donation I gave. great work!
