The Vray sun & sky is a physically based system that works in
conjunction with the Vray physical camera.
to create: top viewport, create tab/ lights/ Vray/ Vray sun
Click and drag towards the target, click yes to place a Vray sky in
the environment slot. Go to the front viewport and raise the sun up. Low angles
tend to work well.
Through the Vray camera you can adjust the exposure values to gain the
correct exposure. I turn off vignetting and do this in post.
As you move the sun position, the Vray sky dynamically changes to
correspond. The sky is brighter in the sun's direction. The amount of
sky light also changes.
The sun is set at a default sun intensity value of 1.0. Initially
leave this alone.
It is an arbitrary figure. The actual intensity of the sun does
change. You can see this if you create a standard 3ds max sun system.
Set the location, select the sun and change the time of day, the sun
multiplier changes. It is possible to create a regular 3Ds max direct light sun and link it
to a daylight system. The multiplier won’t change, but that's another
story!
As the sky is placed in the 3ds max environment slot it is generating
both the background image and the corresponding environment lighting.
The environment background is responsible for reflections.
Press 8 to open the environment dialogue.
If you un-tick the active Vray sky and leave the black default colour
active you will be left with the sun light only.
If you do change the Vray sun multiplier then you will also change the
Vray sky intensity too. They are linked. The system works well for a
sunny day, with lots of contrast between the sun and shade.
There is a way to change the sun intensity while maintaining the same
environment intensity.
Drag the Vray sky from the environment slot into the material editor
and tick manual sun node. Once you click this the sky will turn very
bright. This is because you haven't specified a node to act as a sun.
It is in essence a sky without any guiding star, sorry, so it appears
at full brightness, and won't have any bright spot. You can use this
if you want an evening sky. Just turn down the intensity value.
Click the button to set sun node and select the sun. It will return to
normal. You can now change the sun values in the modifier panel
without affecting the sky. The sky parameters are set through the
material editor. The sky will still track the sun and you will get the
brighter area of the sky.
You can make the sun size larger to create softer shadows, change the intensity.
you can change the sky and sun colour by adjusting the turbidity and
ozone. I usually set turbidity (atmospheric particles or stuff in the
air!) at 2.4. the ozone is the sun colour, set to 3 the sun colour
will
Typically the sky is blown out. It is possible to lower the intensity of the background sky without
affecting the GI. I sometimes do this just a bit to subtly bring back
the colour of the sky. Go easy with this! Too much difference between
the lighting and the background can look really bad!
Firstly select a new material slot and choose an output map. Name it
BG (background). Instance copy the Vray sky to the output 'none' map.
Now instance copy the output map into the environment slot.
press F10 to open the Vray dialogue. Locate the environment tab and
activate GI override. Instance copy the first Vray sky here.
the GI Override literally overrides the GI. so instead of the
background providing the illumination, this slot is taking care of it.
You can just turn this on and choose a colour, then change the
multiplier, however because we have placed a Vray sky in the slot, the
multiplier won't work. we have to change the intensity via the
material editor. We don't actually want to change it but just so you
know!
Because we instance copied the sky to the output, it will adapt to any
position changes we make to the sun. to change the intensity, adjust
the output amount. Only by a little! Just to bring a touch of tonality
back from a blown out sky.
Reflections
Remember, the background sky is still generating our reflections. the
Vray sky is nice but other than the tonality, it does not have any
clouds or much else to generate reflections. Let’s switch it for an
appropriate HDR.
From the material editor choose a Vray HDRI map, then choose an HDR.
Set to spherical environment and instance copy into the background
environment slot. Render it and see how it looks. If it is too bright
change the intensity through the material editor. If you want to
change the rotation change this through the horizontal rotation in
material editor too. it is based on 360 degree rotation. the HDR is
providing the background and the reflection, the Vray sky is providing
the GI, and the sun is providing its light.
The other two swatches in the vray environment dialogue are:
reflection/refraction override and purely refraction override.
if you want you can place a different map in the first slot and this
will override the ref and refraction. maybe you are happy with the
background but want to rotate or boost the reflections.
if you place your background hdr in the reflect/refract swatch and
render with the max environment background unticked and set to black,
you will see your reflect/refract image through the glass windows if
they look on to your background. so that is why the refract swatch
exists. you can enable it and set it to black or override it and
choose a different map. that would be very confusing!
there is another method...
Vray dome light technique.
create a dome light, click the texture swatch and select Vray HDRI.
Drag this to the material editor and choose an HDR file, set to
spherical mapping.
we will control the rotation of the HDR by linking the rotation of the
actual dome light object to the horizontal rotation of the HDR image
in the material editor.
right click the dome light, wire parameters, horizontal rotation, it
will prompt you to select an object to wire with, select the dome
light again, texture, horizontal rotation, a dialogue box will appear,
you will see the rotation of the dome light on the left, the resulting
HDR rotation on the right, make sure the rotation is -Z (minus Z) as
the rotation is inverted. click the arrow to link them.
the dome light defaults to being visible, (you will see the hdr as the
background) and is acting as a direct light with 8 subdivisions.
reflections and specular is also on.
If you activate Vray RT you will have see the scene is lit with the
HDR, the background is visible, and reflections are being generated.
so far so good!
rotate your dome light and you will see the sky rotate too. nice.
hdri's that are created with the sun in the centre of the image
usually result in the sun being oriented due east. so you can gauge
the direction of your sun from this. rotate the dome 90 degrees
counter clockwise and the HDR sun will be oriented from the north.
there are a few more things to consider: exposure control, the direct
light nature of the dome light, and the lack of an alpha channel.
grain and speed will be examined. a multi layered work flow will be
discussed too.
sun alignment with the dome to help rotation can help too.
1: exposure.
ideally all HDRI files would be calibrated to correspond with an
exposure value (EV) then you could look it up on a chart and set your
vray physical camera to suit. well they are not! so what work flow to
use?
well even with EV charts to help, you would have to adjust your camera
if you are looking towards or away from the sun. so they are only a
rough guide. even in the real world a camera has to compensate for a
polarising filter by about 2.4 stops. so it's a starting point.
in the interest of getting stuff done and not getting bogged down in
exposure world, use the sun system as a guide and adjust the HDR
intensity in the material editor to suit. the Vray dome light
multiplier is 30 by default. this works with the Vray camera, but if
you don't want to use exposure control you can set a value of 1 or 2
for a white dome light. if I am using hdr's in this situation I just
leave the dome at 1 and head over to the material editor.
orienting the vray sun
it's pretty simple to create the Vray sun, but if you are combining it
with an HDR it might be handy to link the rotation to a dummy object.
you don't have to do this, I sometimes do because if I have set my sun
angle and adjusted it's intensity, manually moving the sun could move
it outward, therefore affecting the intensity.
so create your sun, place the target at 0,0,0, and in the top viewport
make sure the sun is to the right. (east) and up slightly.
create a dummy object and place at 0,0,0, link the sun to the dummy.
rotate the dummy and the sun will rotate. refer to your dome light
rotation and match them up. I don't use the HDR as a linking object
because I like to keep them separate.
you can still adjust the height of the sun by just moving it down.
sun tip: keep it low! early morning or late afternoon going into evening.
dome light settings
essentially the dome light is working on the same concept as the good
old hemisphere of spotlights we used to use in the old days, the vray
dome light is by default acting as a direct light. this means that
global illumination does not need to be on for it to work. shadow
refinement and image grain are controlled by the lights subdivision
parameter. default is 8, 16 is ok, good quality is 32 - 50, which is a
lot, and will render very slowly!
you don't always need global illumination, to render a separate pass
for animated people this is good, the other geometry is set to matte
object, alpha contribution of minus 1, glass turned off. moving
objects are tricky using GI as you have to calculate the GI for every
frame, and render in such a way to avoid flickering. so the static
architecture is calculated then rendered, but for moving objects GI
isn't used and they are composited afterwards
visible to diffuse, reflection, specular are checked, enabling you to
see the map in the background
the dome light differs from simply placing an image in the override
swatches because it gives you more control. it also has importance
sampling, which it uses to determine the action areas in your map, ie
the sun location or other details.
there is the option to make the dome light act like the GI override
slot, which calculates the light with the irradiance map. the store
with irradiance map box. you can set the samples to 8 and the quality
of your shadow definition will be determined by your irradiance map.
this is much faster. because it is using global illumination this must
be activated or.. no light!
this option exists in all Vray lights, however for things like down
lights I probably wouldn't recommend it, especially if you are making
low GI setting tests as the shape of the light will be calculated
based on that, ie you will have a large and undefined shape and it
will look awful. also, if you are using the light select Vray element,
this only works for direct lights.
other lighting methods
switch the sun for a Vray planar light. it's a big area light, or
light emitter. this is good for creating nice soft lighting.
very important: turn off fall off. I use a dummy object as a look at
constraint to act as the target, then play with the look at axis, I
think Z is correct, and flip the light. you can also link the light to
the dummy and control it's rotation by rotating the dummy itself.
you control the shadow sharpness by adjusting the lights size, the
larger the light, the softer the shadows. I like it because I can
control the sun colour easily, and even place an image in the texture
slot! you may be able to use this to create animated clouds if you
have an image sequence, or animate a noise map.
you can also use a standard direct light as a sun however I find the
shadows aren't as good as the Vray sun. it is easier to control the
colour though.
dusk shots
set an appropriate EV for your camera.
your interior lights can be 'real world' ie luminous power, and as
close to real world size as possible. a typical downlight has a half
width of 25mm x 25mm and a luminous power of ~1200, with a colour
temperature of between 3800 - 4800. you can set the directional
parameter to .25 to create a slight cone.
illuminate the scene without the sun. purely environment lighting.
you can use an HDR, you can use a Vray sky. leave the sky linked if
you want to show a lighter area where the sun is setting. if you want
an early evening to twilight feel you can grab a Vray sky straight
from the get map department and take the multiplier down super low
conjunction with the Vray physical camera.
to create: top viewport, create tab/ lights/ Vray/ Vray sun
Click and drag towards the target, click yes to place a Vray sky in
the environment slot. Go to the front viewport and raise the sun up. Low angles
tend to work well.
Through the Vray camera you can adjust the exposure values to gain the
correct exposure. I turn off vignetting and do this in post.
As you move the sun position, the Vray sky dynamically changes to
correspond. The sky is brighter in the sun's direction. The amount of
sky light also changes.
The sun is set at a default sun intensity value of 1.0. Initially
leave this alone.
It is an arbitrary figure. The actual intensity of the sun does
change. You can see this if you create a standard 3ds max sun system.
Set the location, select the sun and change the time of day, the sun
multiplier changes. It is possible to create a regular 3Ds max direct light sun and link it
to a daylight system. The multiplier won’t change, but that's another
story!
As the sky is placed in the 3ds max environment slot it is generating
both the background image and the corresponding environment lighting.
The environment background is responsible for reflections.
Press 8 to open the environment dialogue.
If you un-tick the active Vray sky and leave the black default colour
active you will be left with the sun light only.
If you do change the Vray sun multiplier then you will also change the
Vray sky intensity too. They are linked. The system works well for a
sunny day, with lots of contrast between the sun and shade.
There is a way to change the sun intensity while maintaining the same
environment intensity.
Drag the Vray sky from the environment slot into the material editor
and tick manual sun node. Once you click this the sky will turn very
bright. This is because you haven't specified a node to act as a sun.
It is in essence a sky without any guiding star, sorry, so it appears
at full brightness, and won't have any bright spot. You can use this
if you want an evening sky. Just turn down the intensity value.
Click the button to set sun node and select the sun. It will return to
normal. You can now change the sun values in the modifier panel
without affecting the sky. The sky parameters are set through the
material editor. The sky will still track the sun and you will get the
brighter area of the sky.
You can make the sun size larger to create softer shadows, change the intensity.
you can change the sky and sun colour by adjusting the turbidity and
ozone. I usually set turbidity (atmospheric particles or stuff in the
air!) at 2.4. the ozone is the sun colour, set to 3 the sun colour
will
Typically the sky is blown out. It is possible to lower the intensity of the background sky without
affecting the GI. I sometimes do this just a bit to subtly bring back
the colour of the sky. Go easy with this! Too much difference between
the lighting and the background can look really bad!
Firstly select a new material slot and choose an output map. Name it
BG (background). Instance copy the Vray sky to the output 'none' map.
Now instance copy the output map into the environment slot.
press F10 to open the Vray dialogue. Locate the environment tab and
activate GI override. Instance copy the first Vray sky here.
the GI Override literally overrides the GI. so instead of the
background providing the illumination, this slot is taking care of it.
You can just turn this on and choose a colour, then change the
multiplier, however because we have placed a Vray sky in the slot, the
multiplier won't work. we have to change the intensity via the
material editor. We don't actually want to change it but just so you
know!
Because we instance copied the sky to the output, it will adapt to any
position changes we make to the sun. to change the intensity, adjust
the output amount. Only by a little! Just to bring a touch of tonality
back from a blown out sky.
Reflections
Remember, the background sky is still generating our reflections. the
Vray sky is nice but other than the tonality, it does not have any
clouds or much else to generate reflections. Let’s switch it for an
appropriate HDR.
From the material editor choose a Vray HDRI map, then choose an HDR.
Set to spherical environment and instance copy into the background
environment slot. Render it and see how it looks. If it is too bright
change the intensity through the material editor. If you want to
change the rotation change this through the horizontal rotation in
material editor too. it is based on 360 degree rotation. the HDR is
providing the background and the reflection, the Vray sky is providing
the GI, and the sun is providing its light.
The other two swatches in the vray environment dialogue are:
reflection/refraction override and purely refraction override.
if you want you can place a different map in the first slot and this
will override the ref and refraction. maybe you are happy with the
background but want to rotate or boost the reflections.
if you place your background hdr in the reflect/refract swatch and
render with the max environment background unticked and set to black,
you will see your reflect/refract image through the glass windows if
they look on to your background. so that is why the refract swatch
exists. you can enable it and set it to black or override it and
choose a different map. that would be very confusing!
there is another method...
Vray dome light technique.
create a dome light, click the texture swatch and select Vray HDRI.
Drag this to the material editor and choose an HDR file, set to
spherical mapping.
we will control the rotation of the HDR by linking the rotation of the
actual dome light object to the horizontal rotation of the HDR image
in the material editor.
right click the dome light, wire parameters, horizontal rotation, it
will prompt you to select an object to wire with, select the dome
light again, texture, horizontal rotation, a dialogue box will appear,
you will see the rotation of the dome light on the left, the resulting
HDR rotation on the right, make sure the rotation is -Z (minus Z) as
the rotation is inverted. click the arrow to link them.
the dome light defaults to being visible, (you will see the hdr as the
background) and is acting as a direct light with 8 subdivisions.
reflections and specular is also on.
If you activate Vray RT you will have see the scene is lit with the
HDR, the background is visible, and reflections are being generated.
so far so good!
rotate your dome light and you will see the sky rotate too. nice.
hdri's that are created with the sun in the centre of the image
usually result in the sun being oriented due east. so you can gauge
the direction of your sun from this. rotate the dome 90 degrees
counter clockwise and the HDR sun will be oriented from the north.
there are a few more things to consider: exposure control, the direct
light nature of the dome light, and the lack of an alpha channel.
grain and speed will be examined. a multi layered work flow will be
discussed too.
sun alignment with the dome to help rotation can help too.
1: exposure.
ideally all HDRI files would be calibrated to correspond with an
exposure value (EV) then you could look it up on a chart and set your
vray physical camera to suit. well they are not! so what work flow to
use?
well even with EV charts to help, you would have to adjust your camera
if you are looking towards or away from the sun. so they are only a
rough guide. even in the real world a camera has to compensate for a
polarising filter by about 2.4 stops. so it's a starting point.
in the interest of getting stuff done and not getting bogged down in
exposure world, use the sun system as a guide and adjust the HDR
intensity in the material editor to suit. the Vray dome light
multiplier is 30 by default. this works with the Vray camera, but if
you don't want to use exposure control you can set a value of 1 or 2
for a white dome light. if I am using hdr's in this situation I just
leave the dome at 1 and head over to the material editor.
orienting the vray sun
it's pretty simple to create the Vray sun, but if you are combining it
with an HDR it might be handy to link the rotation to a dummy object.
you don't have to do this, I sometimes do because if I have set my sun
angle and adjusted it's intensity, manually moving the sun could move
it outward, therefore affecting the intensity.
so create your sun, place the target at 0,0,0, and in the top viewport
make sure the sun is to the right. (east) and up slightly.
create a dummy object and place at 0,0,0, link the sun to the dummy.
rotate the dummy and the sun will rotate. refer to your dome light
rotation and match them up. I don't use the HDR as a linking object
because I like to keep them separate.
you can still adjust the height of the sun by just moving it down.
sun tip: keep it low! early morning or late afternoon going into evening.
dome light settings
essentially the dome light is working on the same concept as the good
old hemisphere of spotlights we used to use in the old days, the vray
dome light is by default acting as a direct light. this means that
global illumination does not need to be on for it to work. shadow
refinement and image grain are controlled by the lights subdivision
parameter. default is 8, 16 is ok, good quality is 32 - 50, which is a
lot, and will render very slowly!
you don't always need global illumination, to render a separate pass
for animated people this is good, the other geometry is set to matte
object, alpha contribution of minus 1, glass turned off. moving
objects are tricky using GI as you have to calculate the GI for every
frame, and render in such a way to avoid flickering. so the static
architecture is calculated then rendered, but for moving objects GI
isn't used and they are composited afterwards
visible to diffuse, reflection, specular are checked, enabling you to
see the map in the background
the dome light differs from simply placing an image in the override
swatches because it gives you more control. it also has importance
sampling, which it uses to determine the action areas in your map, ie
the sun location or other details.
there is the option to make the dome light act like the GI override
slot, which calculates the light with the irradiance map. the store
with irradiance map box. you can set the samples to 8 and the quality
of your shadow definition will be determined by your irradiance map.
this is much faster. because it is using global illumination this must
be activated or.. no light!
this option exists in all Vray lights, however for things like down
lights I probably wouldn't recommend it, especially if you are making
low GI setting tests as the shape of the light will be calculated
based on that, ie you will have a large and undefined shape and it
will look awful. also, if you are using the light select Vray element,
this only works for direct lights.
other lighting methods
switch the sun for a Vray planar light. it's a big area light, or
light emitter. this is good for creating nice soft lighting.
very important: turn off fall off. I use a dummy object as a look at
constraint to act as the target, then play with the look at axis, I
think Z is correct, and flip the light. you can also link the light to
the dummy and control it's rotation by rotating the dummy itself.
you control the shadow sharpness by adjusting the lights size, the
larger the light, the softer the shadows. I like it because I can
control the sun colour easily, and even place an image in the texture
slot! you may be able to use this to create animated clouds if you
have an image sequence, or animate a noise map.
you can also use a standard direct light as a sun however I find the
shadows aren't as good as the Vray sun. it is easier to control the
colour though.
dusk shots
set an appropriate EV for your camera.
your interior lights can be 'real world' ie luminous power, and as
close to real world size as possible. a typical downlight has a half
width of 25mm x 25mm and a luminous power of ~1200, with a colour
temperature of between 3800 - 4800. you can set the directional
parameter to .25 to create a slight cone.
illuminate the scene without the sun. purely environment lighting.
you can use an HDR, you can use a Vray sky. leave the sky linked if
you want to show a lighter area where the sun is setting. if you want
an early evening to twilight feel you can grab a Vray sky straight
from the get map department and take the multiplier down super low
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