How can I move a dome light lower? (to avoid the horizont/ground in reflections)

[Alexx31]

I have often the horizont in reflections, but can't move the domelight lower, for seeing more the upper part of the sphere. how to achieve this?
Often the ground is less interesting than the bright upper part, especially if there are from a city or trees reflections.

Thanks

[vladimir_krastev]

Hi you could edit the image itself.
Also you can rotate the VRay Dome light so that the horizon is lowered but on the opposite side it will be lifted so you need to keep this in mind. You need to enable the "lock texture to icon" when rotating the dome light:





Another way to rotate your hdri is by using the options in the VRayBitmap:

[Alexx31]

Thanks, this is what I already did. I remember in Maya it's possible to move the vertical position. Rotation doesn't help, because you get more problems on the other side.
If it's in Max not possible to move it, couldn't be a stretching of the top half-sphere towards the bottom implemented? (Or is there already a hidden way to do so?)

[vladimir_krastev]

Hi when you scale the dome light itself nothing will change. The hdri texture is mapped over a spherical model and it is not directly related to the dome light's gizmo geometrical properties with the exception of rotation.
Actually there is an OSL that can shift the horizon. Here is how to access it in 3ds max 2022:



This is the setting that shifts the horizon line:



I have also logged an improvement task in our system under VMAX-11838 for this functionality to be added.

[seandunderdale]

Can this be added to Maya also, please?

[kosso_olli]

There is a long standing request dating back to 2017 to enhance the domelight projection features and to add scaling factor influencing anything above the horizon line. I will not link the thread to this anymore, because I gave up on it. It is still desperately needed, though.

[Joelaff]

I just grid warp my HDRI in Fusion when I need this. Though it would be nice to have a built in option.

The OSL shader is interesting.

[^Lele^]

It can be mapped as spherical with the max standard coordinates set, and then stretched/shifted via the usual controls.
Notice rotation will then have to be specified with the U offset, if not tied to the domelight rotation.

[kosso_olli]

It can be mapped as spherical with the max standard coordinates set, and then stretched/shifted via the usual controls.
Notice rotation will then have to be specified with the U offset, if not tied to the domelight rotation.

This is the same as using the Crop/Place feature of the VrayBitmap and has a drawback: The ground will slowly start to appear in the zenith of the sphere.
There is no way around a rework of the domelight projection.

[^Lele^]

If one checks tiling off, that won't happen.
Of course, then black, or the result of a composite with the preferred colour, would appear.
Non-uniform distortion can't be applied, currently, via a map alone, and should be applied to a mapped geometric sphere instead.
EDIT: see attached (n.b. the dome is set to not affect reflection or specular, ofc.)

[Joelaff]

I usually handle that wraparound thing with:

Mirror on for both axes. U and V offset and Tiling amount all 0.5. This way the map stays in the same place as with tiling on, but does a mirror at the edges.

But, yes, still need proper controls for dealing with domes.

[^Lele^]

I'm afraid mirroring only works with some very specific case (most maps won't have a nice uniform tint at the top.).

But, yes, still need proper controls for dealing with domes.

I'm not sure what kind of controls one may have with a couple of sliders in a map, when a primitive sphere and a single FFD deformer goes much farther without any issue.
Alas, this is a long standing talk that i'd rather not pick up again: There are valid reasons why it hasn't yet been implemented the way it's been asked, chief one being the ten seconds setup i posted above, setup essentially mirrored by the likes of VRED, often touted as the env. mapping paragon.

[Joelaff]

I'm afraid mirroring only works with some very specific case (most maps won't have a nice uniform tint at the top.).

Surprisingly, most are close enough when they are skies, unless you are dealing with something directly reflecting the zenith (like a car).

I'm not sure what kind of controls one may have with a couple of sliders in a map, when a primitive sphere and a single FFD deformer goes much farther without any issue.

Are you suggesting using this, flipping the normals in, and then using it with a VRayLightMtl. I have done this, but I thought this rendered more slowly than a dome light with a texture.

The grid warp in external app is what I normally use for HDRI balls anyway.

No doubt many ways to approach it.

[^Lele^]

Surprisingly, most are close enough when they are skies, unless you are dealing with something directly reflecting the zenith (like a car).

Precisely.

Are you suggesting using this, flipping the normals in, and then using it with a VRayLightMtl. I have done this, but I thought this rendered more slowly than a dome light with a texture.

Not at all when used as a reflection probe only, as GI is still done accurately and quickly by the domelight
In fact, this is the by-the-book approach with *any* kind of reflection mapping, since time immemorial.
Map your textures on geo using traditional UV tools, use a lightMtl (emit on backside if needs be), set up object and v-ray props, and render away.
It's truly a simple solution, used in DCC apps and compositing apps both.

The grid warp in external app is what I normally use for HDRI balls anyway.

No doubt many ways to approach it.

It can definitely be better looking if the warping is done with the right tools that can do sophisticated interpolation for the stretched and squashed pixels, but as an in-app approach, this is mighty fine and, you're correct, one of many approaches that can be brought to bear on the specific problem.

[Joelaff]

Not at all when used as a reflection probe only, as GI is still done accurately and quickly by the domelight
In fact, this is the by-the-book approach with *any* kind of reflection mapping, since time immemorial.
Map your textures on geo using traditional UV tools, use a lightMtl (emit on backside if needs be), set up object and v-ray props, and render away.
It's truly a simple solution, used in DCC apps and compositing apps both.

No doubt. This is how I've been doing it since the days of HDR Shop and LightWave. I just didn't know if you were using a VRayLightMtl for the GI illumination as well, or using that only for reflections and using a Dome Light for GI. I often use a lower res/blurred map for GI, and a full res/sharp map for reflections (again, since back in the old days).

I prefer to flip the normals on the sphere and cull backfaces in the display so I can see into the dome while I work. (Comes more from LightWave where the default is to cull backfaces both on display and render, which I prefer.) But emit on backside works.