I bumped into some issues.
My scene setup is pretty basic. Vehicle with double sided windshields (shell) , HDRI for the lighting and a Backplate.
Now, when I look through my windshield, I see the HDRI and not the actual backplate.
In order for that to show up, I have to check in " Thin", but if I do so, I lose the nice glass effect from my windshields.
Is there any way to get proper refraction on my widnshields without checking in " Thin " ?
Note;
-I already tried to plug in the backplate into the Enviro Refr slot in the Windshield material(s). (this ended up causing refracted bits of my backplate on unrealistic spots)
-Already tried having normal glass on the outside of the shell, and thin one on the inside. (…nope)
-Tried all 3 projection modes in the shadowcatcher.
What occured to me is basically adding a plane behind my vehicle with the shadowcatcher material, but this might slow down my render, cause shadows (if they cannot be turned off in the object properties) so on, so on.
I’d greatly appreciate if someone has some intel on this. Not sure if it’s a bug or not.
Thank you!
Nope.
That way I get every single glass messed up. Headlights included, which are not supposed to get refractions from the backplate.
As I said before, the closest I got to a solution is adding a plane behind the windshield and add the Shadowcatcher to it.
However this will generate a dark square where the plane is, even if I turn off receive/cast shadows.
Yes, facing this often. The solution that works and that you mentioned is to use a plane with the backplate mapped on it but it’s a workaround that doesn’t work well in some situations (animations or situations where the backplate is too close to the scene’s geometry causing visible changes etc.). What would help is another map slot called ‘backplate map’ or so that would work differently from the refractions override.
This should work straight away… Can anyone provide with examples (images, scenes)? I am especially interested in how you are making the backplate, and loading the HDRI.
This is my workaround this issue , with the plane mentioned before.
This way I can see the backplate if looking through the windshields. (thin-not activated) (both clay and interactive image attached)
If I don’t have the plane there, he will not project the backplate behind the windshield, but the HDRI. (thin-not activated) (didn’t have a image attached of this one)
Third case would be by simply checking in " thin " , but then I lose a lot of detail from the windshields and they basically look flat.
Hi. At bottom of the map rollout in Corona mtl there are two slots for BG reflection override and BG refraction override. So if you create a glass material (solid - not thin) specifically for the windshields and put the backplate into the “BG refraction override” slot, then I believe it should work as needed.
Moving the plane further away did stop the blackening.
However this is still a lot of work for such a simple , hate to call it “issue” .
I really hope they will add some sort of a direct override for this in the future.
If I’d have objects around the vehicle, I’d be screwed with this plane.
I will just ignore your tone there and ask you a simple question instead.
What if I want to animate something.
I.e. a vehicle moving across the scene. I guess you would prefer animating a plane behind the vehicle instead of coming up with a proper solution, don’t you ?
"And how would you suggest resolving it differently? "
Doubt I am the one who should have the answers for this.
The plane method extension will also project misc reflections onto a car. Also instead of fixing the problem you are making excuses and temporary solutions. Corona is a fantastic engine and quality is great, but this is a very simple request that should not be hard to fix. Vray has the ability to have the refection be normal, corona is beating vray in almost every aspect so why not make this as good also.
Also as far as image sequence backplate. You said some advanced scene blockout would need to be done. That may be recommended but not needed. I have done a complete Ford Commercial and did nothing but animate the vehicle and slightly hdr, client was happy and work looked good. So no need to do something complex if it looks fine.
Let’s just say a car spinning around.
Try out another theory with this then. Start scaling up the plate behind the vehicle, simulating the upscaled plane idea you just told me.
Now check the reflections on the vehicle.
You will be able to see the big plane on your clear coat.
Obviously you could haggle it out with a regular vehicle. However if I would have 500 frames to render, it would be hard to spot where that thing reflects up on the vehicle.
For most this would give a stroke after 500 frames.
Then there would be another issue if it’s a bigger vehicle, god forbid a Sci-fi thing.
Rawalanche - The refraction override is almost doing it but the only issue I noticed for me when trying to use it, it will put the image in areas that should see other things, it kills the life of the headlights etc.
I dont like comparing things to vray because its not fair to do so. But for reference, in vray, whatever I have in my environment background image, that shows up through the back of my glass, refraction remain the same but it shows the bg image in back of glass.
On the other hand, the glass in Corona usually has alpha, so if you bring it into AE or Photoshop without showing background in render you can put backplate in there and it will be fine lol.
My backplate never illuminates anything even with GI on because I use a dome light. I created the shapes with no shell for a quick example. Also as long as you use a dome light with spherical checked your backplate will never show up through solid objects. I know exactly what issue you are talking about, but using a dome fixes that haha.
Trust me, this works 100% accurately when I am setting up a proper scene.
I am attaching some shots I have done in past with Vray so you can see how the glass works just fine, this was same method with no backplate plane.
Aha! Okay so I did the test Rawalanche.
I see what is happening. Vray and Corona have the same concept inverted lol.
I agree with you on the ball sample, vray will only do this if I do not override backplate image, which makes it actually a bigger pain than Corona and actually corona wins here with it being easier.
But I do have to still stand behind the logic that when you do refraction override in Corona it does behave a little bit different than when you have a backplate image in Vray env slot.
I guess at this point its either one way or another, in this sense the foundation of Corona is more accurate if you want to use balls and such, however it does backfire in the sense of refraction override but that can be fixed with a plane behind windows.
Just knowing solutions to problems, still cgi so it can never be 100% easy hahahaha.
Creates a plane that matches your backplate input and takes up the extent of your camera’s field of view at all times and moves along with your camera’s movements/transforms.
I haven’t joined in the conversation between you two gentleman, because my knowledge is still not thorough enough about the subject.
However. Blunt idea.
Getting correct results is possible. Via the plane. So the end result is achievable.
What if the camera or the material has an option, that will make selected objects act as if they were Glass with a back-plane behind them ,determined angle by the camera and its target.
I’m only spit balling ideas here.
Would that be possible in some way ?
