HDRI Backdrop issue


I am starting to use Unreal. in the manual how to apply HDRI background image as a backdrop I tried to make all necessary adjustments but it is still distorted. The mesh was configured as EnviroBoxSharp and I defined the maximum dimension (4096). I attached a screenshot.

Thanks for any help.

After reading

Could you please post the HDRI settings in a screenshot or two?


Maybe your HDRI is spherical and the HDRI backdrop mesh’s shape in Unreal is a tear(ish) shape so the bottom of a spherical image will be distorted…

Thanks for replying.

@Makigirl As I said in my first post I defined the mesh as EnviroBoxSharp.

One thing is the Imported and the Max In-Game resolutions need to be exactly the same. Currently, yours is Imported: 4096 x 2048, and Max In-Game: 2048 x 2048…
Some of the other import settings aren’t showing in the last screenshot. What are those?

Have you tried changing the Projection Center value? Z=500 is rather high, and could be a part of the skewing.

If you want use this particular HDRI, then i would recommend a different Environment Dome than EnviroBoxSharp or any of those standard domes. There is a Sphere with inverted normals named “Sphere_inversenormals” (it´s part of the Engine content, so you have to make that visible first), take that as Environment dome, and those deformations are gone. With that sphere, it is almost like camera projection, but you can move around and see position change in your HDRI. And because it is an actual sphere, and not just a half of a sphere like the normal dome, you can set the projection center to zero.

How to find this Sphere_InverseNormals dome and how it will look with the HDRI Backdrop:

Nah, it´s a combination of an unlucky HDRI texture and dome, i think, this HDRI would not work well with any standard dome, as it is made from a very small room, that would not allow much movement without distortions. I guess, there is such a thing as a minimum size for real life places, that needs to be uphold to work well with HDRI backdrops. And the original shop/room seems to be way to small/below that limit.

And that resolution you mention, you cannot go higher than the latter number/height of the cubemap texture in your max ingame resolution :slight_smile: so you want to be as close as possible to the height of the cubemap. With that texture, even if you set the slider to 4k, it will stay at 2048, but it´s not a problem, it still uses all of the texture at full resolution.

So, @suthriel appeared to solve your problem. I have a question for suthriel, though, about those three resolutions when importing a cubemap for HDRI.

If the slider stays at 2048, is it because the texture’s Imported Value, which is 4096 x 2048, where 2048 is the second value in the res? or is it because of the original texture having a resolution of 2048, or rather, that it was rendered / saved at a 2048 resolution before import? I know it kinda sounds like the same question or the same answer could be derived from either question, but what I’m asking is if the initial resolution before import of the cubemap is becoming a limit in Max In-Game Res in Unreal?

From what i have seen, the original texture/image/cubemap resolution (before importing it into the engine) becomes the max ingame resolution, unless the imported texture is way bigger, than what the engine can handle, then it will be the max res the engine allows (was it 16k?).
Don´t ask me why it always uses a squared resolution for cubemaps, which obviously are not squared ^.^ I guess, thats an engine thing, how it handles all texture (identical dimensions for all sides), and the engine makes sure, that you don´t create a texture, that is bigger/higher than your original image, that you have imported.

Or if it is in between two resolutions the engine supports, then you can only go with the next lower one. Once i had a HDRI with 10000x5000, and the engine did only allow 4096 as max resolution. The next higher res would have been 8k, which would have been way higher than the original height of 5000 pixels from the HDRI, so i could only pick 4096 in that case. Ok, that was UE 4.19 or so, so not sure, if this still is the case, but i think so.

Awesome! Many thanks, @Suthriel. I will replicate what you showed in the video. I need to use some store environments for my demo and I’ve only been able to find this HDRI so far.

Is it possible to use background images without being panoramics, as if it were sceneries, in case of the movements are disabled?

Not sure, if i understand your question correct, but the HDRI backdrop requires panoramic/spherical textures, it´s designed for those kind of textures. However, nothing would stop you to just google a normal flat picture of an interior you like, and then add an additional flat plane into the scene, that will act as your real background, and give this flat plane your normal flat picture as (unlit or emissive, maybe masked too) material. Then you would have the HDRI backdrop for lighting your scene, while the flat plane would simply act as a background object with the interior, that you like.

Thanks. This is exactly what I need for some stages of the demonstration that I intend to produce. I will try to find an example like this in this forum. I am really a newbie in Unreal.