Thea Rendering - what am I doing wrong?

I have SketchUp Pro. I’m ready to go to the next level of rendering to more realistic images. I’ve tried a few different software systems and gave up after hours of trying to navigate them. Then I gave Thea a try yesterday and spent about 6 hours struggling to figure it out. But my images are grainy, blurry. Not sure what I’m doing wrong. Can one of you help? Should I try a different software program?

I’m working from a very simple SketchUp image to practice. And every rendering turns out terrible. Here is the sketch up iimage with 3 different attempts to render.

Here is another rendering a struggled with that is also very simple. But the rendering is grainy as well. No where close to being successful.

With most renderers that build up the quality over time the longer you give it the less grainy it will look.

Also, check to see if Thea has a preview mode, and that you’re not in that mode.

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Building upon what Colin said, it is also typical of shady areas to be far more taxing on a rendering engine than anything else.

My SketchUp drawings are bright. I don’t understand why the rendering is so dark, and I added lighting with Thea software but it doesn’t improve it. With Thea preview window as I’m struggling to add more light but it’s very slow and often doesn’t update simultaneously. I have no reference to how the lighting is effecting the outcome.

On the tutorials it shows the preview image change as one revises the lighting on Thea. But that’s not my experience. The first rendering was 30+ minutes. then I put a limit of 10 minutes on the rendering output. Either way rendering is grainy.

If I give it more time to render, the image should be better? How much time would you say? I put a limit of 10 minutes on the last few because I became impatient to see how my lighting was effecting the image. The preview wasn’t working simultaneously as I tried to navigate adding light. I limited the output time to 10 min just so I could see what the lighting was doing.

All in all it’s so frustrating to get anywhere with this software. Should I skip it and try a different software? I’m on SketchUp Pro and I’m giving Thea “Hobby” a trial. Even though I’m a professional interior designer.

I’ve tried VRay, Twin Motion, And a couple of others. I just want to be able to render a few scene images for each project to give my clients a sense of what the the finished project will look like (more realistic).

Your images do have a lot of shadows in them. That is going to be taxing.

I also notice you’re on a Mac without a dedicated graphics card that is capable of even handling a rendering. 10-30 minutes is, in this case, not a long time.

I do recommend adding more artificial light if you’re okay with that look. Otherwise you’ll have to give it more time.

If you want to try out a simpler rendering software that can turn out biased rendering (not just waiting longer for photo realism), I recommend Twilight. It can render a passable image comparable to an unbiased rendering (what you’re seeing) in a small fraction of the time.


Maybe it would help to try looking at your models from a photgrapher’s point of view. In the bedroom scene you have no real environment to keep the light in. Build a full room around the bed.

And in both cases you have little in the way of effective lighting. You can compare your SketchUp model’s “lighting” to that of the render. SketchUp doesn’t have any way to show you how the illumination will be handled from your light sources.

Yes. I will try that as well. This is just stripped down scene from a house rendering I developed. The actual drawing has everything in it. 4 bedrooms and 4 baths on the second floor. + main and basement complete. It’s a huge file. I only stripped it down to the bed to practice with the software because it’s so slow already.

Having said that I just plugged in Ambient Occlusion and it’s not bad for a first try. I managed to do this in just under 5 minutes without ever having used it before. (softening the edges on the upholstered areas will improve it). I’ll try Twilight as well.

That looks better but it also looks like the bed and wall are outside in the street on a day with a high overcast.

Can you share the model of one of these with your settings? I can run a render with Thea to see what the issue may be. In the browser “save with dependencies”
With your bedroom scene I can see you still have the sky/ambient light still checked which might not be good to get an accurate render. The main reason for graininess is not allowing the render to run long enough combined with a lot of bounced light. Which of the Thea render engines are you using? You might do well to use the “Presto” one which produces the fastes results.
The blur would be caused by the camera settings - make sure your camera is set to auto focus and pinhole ( unless you are looking for depth of field)



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Okay. I will share the file with you. I know it’s just a bed floating in space but it’s for me to practice on. If it’s an issue that the file doesn’t have a floor, walls, or ceiling I can easily add that. I just wanted to simplify it during this process as I’m learning how to use the software. However, I am uploading the kitchen file.

I think my kitchen file and the bed file is too big to upload.

I tried the Ambient Occlusion on the Kitchen scene and that didn’t turn out too bad. The cabinets are supposed to be all white. But show here as grey in some parts. But it’s a very easy software to use. Probably too easy? I could handle something more complicated I’m just not sure which software is the right fit. I will try Twilight as @monospaced suggested - see how that works.

I can’t seem to upload my sketch up files. I assume because of the size? @whiterabbitdesigncompany although I would be very interested to see what you could do and to help me learn Thea. ~ !The added lighting software is helpful and makes the image look more photo-realistic.

@DaveR don’t have walls, ceiling, &floor on the bed image because I purposefully took everything out of the room to try to minimize the size. thinking it would speed up my trials. But you’re right - totally looks weird without them.

Here is a trial run of Ambient Occlusion for the kitchen. It’s so easy - anyone could do this. But it doesn’t seem to have the additional lighting options that Thea has and the cupboards should be all white. Not grey.

can you do a dropbox link? or similar.

For the light hitting the ceiling to be white, the cupboards would naturally be darker than white. You could fix the image after rendering, to prefer that the cupboards are white and the ceiling is overblown.

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@whiterabbitdesigncompany Here is a link to the DropBox file. It would be great if you could let me know what I’m doing wrong.

Can you upload full model.
there was only the shell?

If you can save it as a Thea zip it will save model with your Thea items.


That’s strange it should be there - not just a shell.
This is a new folder with the SketchUp file as well as the Zip Thea file (although I have no idea what will be in the zip file).