Frustrated with the ground in HDRI's
Serene Night
Posts: 17,602
I have a lot of trouble aligning things properly on the ground in HDRI's. For example I did a beach scene, dropped the beach blanke to the ground, and it renders partially sticking out of the ground. Inevitably characters feet sink into the ground or float above the ground. I use the command to drop the figures so they should be lining up... But no dice. Is there a way to make sure before I hit render that everything is smack dab, on top of whatever is the ground in the HDRI?
Additional factors: I can't always see my HDRI in preview mode- unless I load it first before placing characters in the scene. Since I like to add lighting last, that doesn't really work for me. So inevitably, preview mode shows my figures but no HDRI.
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That's why I only use HRDIs for light or as background, but rarely.
It depends on the HDRI and what you want to use it for. If I use it as a prop the I set the Ground to Manual rather than the default Auto. The D/ Drop to Ground seems to work fine that way. You can also move the object down so that, if using water, the bottom disappears beneath it. These both use HDRI for the Environment. Camera angle and zoom also play a big part in getting things to match the environment. It would be handy if those taking the HDRI would also include the camera settings, f/stop, speed, iso and camera height, so that it would give a starting point for the Studio camera settings. As a photographer I can usually fudge it but not everyone knows about zoom settings, focal lengths and camera position.
I don't know about the missing HDRI in the viewport as it is always in view when I do it.
You will see that I placed both subjects so that their feet look as if they are in the sand.
Click on image for full size.
In this one the Poecupine is standing on the 'ground'. I have other examples posted in my Art thread.
Click on image for full size.
Hey Fishtales you from South Africa?
I use the Auxiliary Viewport before any render, this will highlight any problems you may have. Like fingers sinking into flesh or floating people etc....
The beach picture the models feet are partially beneath the sand, that is somewhat plausible but the porcipine is abou 0.5" - 1" floating above the ground.
Nope, Scotland.
I use the Aux Viewport set to Iray all the time. I just hide it and view it as needed.
Only its front left leg because it is stepping down, the back legs and right front are on the ground............maybe
I tend to not like extreme camera that are included with the HDRI's because they are made to make the hdri look good and frequentlyd distort the figure placed in front of them.
My latest set I picked up I wondered why the camera showed no figures, even though there were figures in the scene- the pa had locked the cameras controls to an orbital view from above. It was pretty useless for me, so yeah, I unlocked the camera, and moved it around, but I prefer a less distoted perspective.
Two ways that help 1) zoom the camera and 2) change the focal length. Doing both together or just the one. Change the height of the camera, I think of it as being on a tripod at approx 6 feet/2 metres or slightly less, think about the photographer setting the camera up and imagine the height from the ground. Moving it up or down and tilting it with zoom and/or focal length changes how and where the figures meet the ground in the image. The Porcupine image was harder to do than the beach one because there are rocks in it which obviously aren't flat but bumpy so getting it close took a lot of time. In this one the seat is part of the HDRI.
I explained here how I got the shadows on the bench seat and back.
From what I have seen elsewhere it was suggested that the lowest bit of geometery in the scene is deemed to be ground level, so I tend to slap in a primitive plane, use that to 'ground align' stuff and hide/delete the plane before rendering.
Yes, if a chraracter's toe is bent, that is considered the ground and all else will float high above that which is frustrating.
I'm mostly just interested in keeping the feet attached to the ground and the HDRI not distorted. I tend to not want too much HDRI in a ascene since it means more photoshop work later
@Serene Night
Do you have an example?
I used an HDRI called Old Industrial Hall for these renders. I'm not sure if it meets your criteria though.
This was a WIP render then the second was the finished render.
Maybe this product will help....
Looks quite interesting
https://www.daz3d.com/iray-hdri-toolkit
Trying to figure out that product. From the previews it looks to just be some primitives with shaders that catch shadows? Anyone know how it works?
The Matte Function is quite easy to use. I used it for this image which is an HDRI with only the girl and the Matte panels geometry. On this one I used it to get the squirrels behind the stick although this is one of my pictures as a backdrop and not a HDRI. On this one I used it to get the reflection of the Faery on the ice, again another backdrop using one of my own pictures.
I use the ground prop of this https://www.daz3d.com/iradiance-pro-series-16k-hdris--rain-city-chicago for other outdoor HDRIs. Works most of the time.
Just as an addendum to this discussion, Fishtales has probably the most helpful and simple suggestion here. The only thing that works for me with HDRIs that refuse to let you place things ON THE GROUND is – as he explains – to set Ground Position Mode to Manual. Then (if Command/Control D doesn't work) manually manipulae the objects in the scene with their parameters to lower or raise to the correct position, and checking in test renders to see where they are. This seems to solve most weird HDRI ground plane issues and continual shadows appearing in odd places in renders.
I have never loaded a HDRI from my content library
I used Everything from Voidtools to find all my HDR and EXR panoramas and copied them all to a separate folder and just plonk them in the slot in environment from there.
I never use the included render or camera settings
This is one of the reasons I use the wet ground texture and render with damp/wet HDRIs. I did a scene about three years ago (horror/psychological - for anyone curious about the image content). In any event, damp HDRIs proved to be glorious with a combination of the wet floor. Made the character actually feel like she was there!
Only advice I can give is listen to Fishtales and, if possible, work with the highest quality HDRIs with an emphasis on connecting the ground to the figure.