I have a problem using linear photometric point lamps
handel_035c4ce6
Posts: 460
I have to make renders in a small room - about 4x4 meters and started with the rendering of the first character which sits near the window. As I don't want shaddow effects and such, but just simply overall equal light into whole room decided to try with 2 linear photometric point lamps, aproximately at 2 meters from the character to render, and he gets a lot of light from the environmental texture from the window right near him. The defalt "power" of the light is 1500 lumens. As it was completely useless I started to increase it... still no change. Googled a lot to find infor but always was finding tutorials about the 3 points light system. Anyway - found oen tutorial at last and learned the point lamps were designer for 3Delight, thats why to be used with Iray their "power" should be at least 50.000 lumens and also the autor advised instead of point geometry to use rectangle and to increase the sizes from 10 to 100. Actually I experimented and increased the power of the 2 lamps to 150.000 lumens and 150% and also experimented with the geometry and sizes of the light source... only to find out the light was unsufficient and unsufficient and unsufficient etcetera.
Please advise!
PS. Also a question - do I understood correctly the cameras can be moved by selecting the camera from perspective vew selector and moving exactly the same way as the perspective view is moved? But the point lights can be nioved only as the objects are moved?
Edit: Doubling the power to 300.000 lumen and closing the lamps to about 1.2 meters was of no real use.
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Comments
FWIW, I have not figured out how to change the sets of 3 lights in Iray. I have one set that sometimes works -- eg. I like the result -- but the other day I found the shadow on the ground in Iray pointing to the right when I wanted it to go left, and no amount of clicking on different pre-made settings would change things or so it seemed.
I have also played with the intensity quite a bit in lots of different scenes and... usually my attempts at change give no discernible result.
I usually use just one camera view... not sure if there is any relationship or comparison in moving the camera and moving the lights.
Some of my lights have little tiles or icons in the Content pane that suggest settings eg. you can move the light or lights up a bit, or sideways... this I don't understand at all.
Not sure what you mean. The point lights are very weak compared to other light sources but they do work. The attached image is with no other lights and environment set to "scene only" and headlamps off. Have you tried distant lights as a test and comparison?
Yes, you can only move the lights like objects and not using the camera controls.
Not sure what you mean. The point lights are very weak compared to other light sources but they do work. The attached image is with no other lights and environment set to "scene only" and headlamps off. Have you tried distant lights as a test and comparison?
You didn't specify you overall light set up, so I can only guess. If your scene is not in a closed room, the Environment/sun light will likely drown out your portrait light set. Try switching to "scene only" to test the lights in isolation. Also make sure the headlamp of the cameras are off.
Photometric lights are Iray, linear point lights are 3Delight. Iray will not do non-physical falloffs in Photoreal mode.
Put both lamps at 600.000 lumens and now the lights are close to ok. But have to withdraw the left lamp as it enters in the camera frame and appears as black disk. Does the disk form is related to the disk geomethry I choosed for the light?
BTW - changing the environment to "scene only" makes the window render checkered as transparent image but nothing is seen through it; tried the option sky-in mode (or something like this) too - the window became flat white.
Overall it seems to me the point lights doesn't have many fans:-)
Point lights work - but you may need to adjust gamma, in render or in post, to see their effect (and they will probably be swamped by any environment map, just as real-worl lights tend to be swamped by daylight).
I think I understood after loading couple of presets I found in this forum and on Deviantart; my frustration was due to the using of "lumens". In the real life light source of 1500 lumens is more then enough to overiluminate a 15 - 20 sqm room, but here a lamp of hundred thousands lumens is next to nothing.
I too would like to know if there's a way to avoid the black disk when you put a disk-shaped spotlight in front of the camera.
Also, I'm wondering why it appears in the first place.
The spotlight should be transparent with only the outlines showing. Didi you turn the "Show Base" under the spotlight Parameters tab on?
Render emitter, under the Light group in Parameters, is the one to hide the light emitter from direct view (it will still show in relfections, or if viewed through another surface).
There are two things playing here. First, the luminous flux with lumens is spread over the entire spherical output of the point light. With real world lights, that total light is directed to a smaller portion of that sphere. IES profiles can simulate this. The bigger thing is that the default tone mapping settings in the Iray render pane are for outdoor lighting (e.g., illuminated by the sun-sky or HDR sources). With indoor light, you need to adjust these with settings to something similar to what you would use on a camera.
Here is an image with a 200W bulb (3000 lumens), a point light using a Philips bulb IES profile casting most of its light downward with a tungsten temperature of 3200K. The tone mapping settings are f2.8, ISO 800, and 1/100 shutter (as suggested by a photography website). It's not the brightest image, but certainly within an order of magnitude of a real-world photo.
Tested it with point lamp. If render emitter is ON, a point lamp with any geometry shows up (for this purpose a "point" is not considered "geometry"). Any 3D geometry shows as white from outside (where the normals should be) and black inside; any 2D geometry is seen black or white depending where the camera is.
Actually why this option is needed?
Maybe this can be of help. I can highly recommend https://www.daz3d.com/ig-photographers-toolbox-photo-lights
It creates accurate photography lights, with familiar tools if you know some photography. Even comes with tutorial. They are not fast lights, but they are accurate.
I am using the standard Iray shader (Uber was I think); is there a way to make the skin render just a little bit lighter (more pale) without increasing the lights?
I see. So... with a... point lights set, up and running, you don't want to have an environment map then, generally speaking?
Hmmm... I have a different, possibly older light set. Maybe I need to upgrade or something.
What did you mean by them not being "fast"...???
I'm not sure I'm familiar with switching to "scene only"... but if you take, say, a 3DL set like Dreamlight's Canyon Extension, there are a bunch of lights that are loaded including a very specific "sun". Lately I've been wondering what the... Iray equivalent is, and when is it included or loaded. For example, take Magix 101's Secret Valley. It's a bright enough day, in this Iray setup, but the sun is at least temporarily obscured by cloud. I'll be darned if I can figure out what makes this scene tick... so different from the Canyon Extensions.
I have to illuminate a small room 4x4 with one half-wall window. I tried to put it on "scene only" but then the window renders checkered as transparent surface but nothing is seen through it.
Use the ceiling set to Emission with the ceiling diffuse image in the map and then lower or raise the Lumen to get the amount of ambient light you need. You can also increase or decrease the light from the Iray Dome to balance the amount of light coming from it.
Like this.
Click on image for full size
Click on image for full size.
If you want more light on the figure then use a Primitive Plane set to Emission and position it near the figure to shine on it where required.
The bar man has one shining on him from the front.
Click on image for full size.
What is the difference in the light between changing the Environment Map and Environment Intensity?
Environment Intensity increase the light coming from the Dome with no Map
Environment Map increases the light from the map which is added to the Environment Intensity which tends to wash out the map image.
So if I want a more clear picture of the image it is better to use lower Env Map value. I see numbers below 1.0 and even 0 and negative numbers are legit too. What will happen with 0 or negative numbers?
Edit: I just tested - w/o any map at all I get just a render with sharp shadows from presumably sun light and transparent background. But I was told Daz cannot use transparent backgrounds w/o using black and white transparent map; what is the use of this setting then (I needed to hang on a wall as a poster an image on transparent background when I was told it needs the B&W map for this)?
Setting Map or Intensity to zero and there will be no light, just black.
With no Map and Draw Dome set to OFF then there will be no dome background just the chequered pattern when rendered this will be an Alpha channel/transparent background where you can add an image in Photoshop.
With no map and Dome set to Draw then there will be a blue sky with sun.
I've been using point lights when there's a specific spot of the image that is dark/in shadow when I don't want it to be.
While this doesn't directly address your question, this link will point you at the best surface settings to manipulate to change the skin and keep it looking natural. From a quick glance, translucency weight and SSS reflectance tint seem like the best options to tweak. A lower translucency weight would make the base color more prominent, and changing the tint to a lighter hue may help as well.
https://thinkdrawart.com/daz-studio-iray-skin-tutorial
Thanks for the link. Actually I started to look more profoundly to the Daz shader settings, and from what I read it seems the SSS reflectance tint can be really helpful. As for the base color it can easily make the skin darker but as it is nearly 100% white from the very beginning it seems it cannot be very usefil to make the skin brighter.
Yeah. I've found that the best way to try to change the skin base color, outside of a using a product like Skin Builder to create my own skin, is to mess around with the base map in GIMP or Photoshop, though that can take time to get right.
Though if you have the cash, I'd recommend Skin Builder - it's relatively easy to use and gives you lots of options. Also, since G3 and G8 are basically the same characters when it comes to the "internals," either of the Skin Builder products will work for both generations. Only note is that the license for each does not allow redistribution with the other generation, so a skin built with SkinBuilder for G3 would work on G8, but you wouldn't be albe to provide a G8 character that uses that skin.
https://www.daz3d.com/skin-builder-8-for-genesis-8-females
https://www.daz3d.com/skin-builder-3-for-genesis-3-female-s
I did this skin in SkinBuilder and it came out exactly as I was hoping.
Right now I have to learn how to make more pale some male skins so money will not help:-)
PS. Nut it is good to know only one of the packages is enough.
"but you wouldn't be albe to provide a G8 character that uses that skin." You mean an interactive 3D character in a 3D game or directly as product for sale, right?
Yes, that is what I meant. The license says that you can only redistribute the same generation.
I've been hoping for a Skin Builder for the G3 or G8 Males for a while. I have some guys who can do with a new "paint job."