There is nothing wrong with setting up a backdrop (or Image Based lighting) like you are doing, if it serves the purpose. The only problem, here, is that there is simply no getting round the fact that you cannot expose for both dark & light situations at the same time. In a more simplistic renderer, that would not be the case, but you would not be able to get the feeling of real light in the scene, either, as you do with a camera, or with Maxwell. There has been another thread, in the main forum (
here), discussing this very topic over the weekend, so you may want to take a look at that discussion, too.
The upshot would be, if you need to have sunlight streaming in through the windows, then I don't see many ways other than doing as the photographers in those tutorials are doing, and combining two shots -- at least you have the benefit of having a perfect tripod, and being able to change some values that are fixed in the real world, albeit likely at the expense of realism. As far as alternate approaches go, this type of thing can be much quicker and easier to deal with when using the Maxwell Render Suite, since there, you can render out different
channels along with the main render, where for example, you would not render twice, but instead insert your backdrop directly, using an
alpha, or
material or object ID output to do accurate masking (a luxury that a real-world photographer never has, since those passes are generated by the renderer, which has full knowledge of the 3D scene, preventing the need to use manual or magic-wand selection).
Actually, it occurs to me, there may be a way of getting at least part of the way there, using the standalone plugin:
- 1. Switch Manager > Environment > Type to Image Based.
2. Set the Background channel to Disabled.
3. Set the Reflection, Refraction, and Illumination channels to Active Sky.
4. Enable Hide from Camera (and maybe also Hide from GI) for your backdrop.
Please note that the backdrop needs to be a group or component in order to enable those rendering options. With this setup, what you should get is your scene, with the backdrop showing up in reflections, but not being visible through the windows -- instead, you will just see black space there, due to the disabled IBL Background channel. Now, you can possibly put your backdrop into the scene manually in Photoshop, rather than actually rendering two different exposures. Lastly, if there is glass in your windows, you might try hiding that to reduce render time a bit, as it's not likely you'd actually see any reflections from it in this scenario.
So please give this a try anyway, and let me know if it helps.
Regarding 3.0.1, I'm not entirely certain on how access to the beta download site is regulated, but you should be able to download the plugin from
this page. If you are not able to access that page, please let me know -- it has been my understanding that if you have the permissions necessary to post here, you will be able to access the page, otherwise I will need to talk to the web people about it.