The immediacy of the feedback, as I can now design in Sketchup and render on the go. Although I'm in the archviz field since 2004 I still don't like to model in 3dsMax in favor of Sketchup and was looking for an alternative to Vray as exporting the model to 3dsmax only for rendering was a huge waste of time.
Thea for Sketchup has become an indispensable tool in my workflow, and I love the friendliness of the community in the official forum, and I am looking forward to contribute to improve the Thea experience for all of us.
1. the lack of news from the devs since the soft is in the hands of Altair.
2. to have to convert all my Vray/max library to be able to use it under Thea workflow.
3. the thea tool's material converter under 3dsmax is really missing some key features, as I spend most of the time removing falloffs, blends, 2sided material, mix, procedural noises, vraynormals, etc. although it could be done automatically if developpers took the time to improve their converter. Since we have fresnel ramp in Presto now I really think we could get an automated conversion of all the falloffs in Vray materials.
4. Noise affair: I feel Thea should align with concurrents and fix the noise in interior renders (when the artificial lighting is more proeminent than sun&sky) or at least propose a denoiser render pass.
5. more tweaking of HDR input and output. the handling of the HDR material is a must-have nowadays and we need more parameters. The tonemapping alone should be taken more seriously as it's a waste of time to be dependent on ArionFX or Luminance HDR to handle the HDR output.
6. I'd like to have a material file format that embeds the texture files as a zip/rar/7zip
7. the thea browser that doesn't sort the files from networked places is annoying, just as the fact that cases matter (A-a shouldn't matter when sorting alphabetically)
8. the network render node (Thea client) keeps it RAM footprint even though the render session is finished.
9. the material editor could be improved a lot.
10. I don't like Thea studio's interface. at all. It's buggy and redundant. I avoid it most of the time.
In general, I have written all my thought here: http://thearender.com/forum/viewtopic.php?f=82&t=19136
As is, Thea render is already a very good render engine.
Mostly for exterior scenes, where sun&sky lighting is predominant.
When artificial lighting is involved (like interiors), the engine shows a lot of noise and it could be a hindrance as the render time needed to get rid of the noisefloor is higher than Vray, Corona, Maxwell, FStorm, or Octane. Vray and Corona use denoiser pass to get rid of the noise even with very low noise threshold. And even then the antialiasing filter contributes to remove the remaining noise.
Yet it's very easy to tweak the lighting setup thanks to Tomasz' Thea4SU interface.
I love Thea because of the people behind it (the developpers) but also because of its ease of use.
I can get good results even without going into material editor.