Help using a mirror
alex_bb8aa5da
Posts: 107
I need to render a scene with a girl looking at her reflection in the mirror. I plan to render the scene twice, with two different outfits. Eventually, in photoshop, the two will be combined so it looks like she is wearing one thing (a boys outfit) but sees herself as something else (a flowing dress.)
I have the DM mirror, but can't figure out how to make it reflect. I usually render individual fiugres (to be combined in photoshop) and use HDRI lights. I don't get how to make lights work with a mirror... could someone possibly talk me through it step by step? I don't need anything else in the scene, like a background room. Just mirror and girl... The help file says "Also note that, just as in the real world, reflection requires a light source. If you have light in the scene, you will have no reflection. " which seems to be a contradition. Any ideas from you amazing folks? -Alex
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First we need to know what rendering engine you are using, Iray or 3Delight, other? Also a link to the product would be helpful!
I am using Iray on a Macbook pro. The mirror is from DM's cave of secrets (https://www.daz3d.com/dm-s-cave-of-secrets). Does the process change if I use a different mirror? I won't be using the actual cave/chamber, just the mirror and some Gen 3 fmale figure. Does that help?
ETA: I also found this mirror in Daz (https://www.daz3d.com/gothika-mirror), which I might get. The promo pictures are somehow showing a non real reflection, which I imagine was photoshoped? But if the process differs whether I use this mirror or the Cave of Secrets one, please let me know :)
I figure it all depends on what shader is being used for the mirror surface, and the lighting of course.
That's a typo, it should say:if you DON'T have light... You need to position the light so it casts direct light on the character for a better result. If you just want a plain mirror reflection you could try applying a regular mirror shader or chrome shader to the mirror surface. I use 3Delight so don't recall the actual names of the Iray shaders, you should find a working shader in your content library/shader presets. Also I'm not sure how Iray renders transparent backgrounds in reflections, maybe an Iray user could enlighten us:)
Forged3D has made a mirror shader for iray available on his DA for free: https://www.deviantart.com/forged3dx/art/Iray-Shader-Mirror-606416242
Apply the shader to the surface of the mirror and you should be good to go.
The angle of your light path is also important - you can only see something if the path of reflection matches with your camera position. It's kind of like playing pool with light. Also, the mirror will not reflect anything if it has nothing to reflect.... so, no "physical" light source like a lamp-geometry, for example.
In the surfaces tab, I think you can play with the metallicity settings to increase or decrease reflection.
this one is by far the better Iray Mirror shader I have seen and used https://www.sharecg.com/v/81125/favorite/21/DAZ-Studio/Iray-Mirror-Shader
After you load the mirror, make sure you apply the settings for it under the Materials Iray folder. That will take care of your shader issues and surface settings, and give you a good reflective surface. Then use either a nice, bright HDRI environment map for your lighting, or rig some mesh lighting around the character (I'd use a ghost light between the character and the mirror, then another one behind the camera). After that, it's all about getting the angle right to see the main character, the reflection, and give you room to Photoshop the two shots together. Playing pool with light, like @BeeMKay says.
@losingsignal and @beeMkay - so do i need a "physical" light source of can i just use HDRI? If I add a physical light source, which of the light options should I select? I can't find the "reflection" setting for the surface for the life of me, but I'm new to shaders and lights. I am loading the iray shader for the mirror, and have been able to get some reflection, but it's all still very dark and i am not sure how to make it brighter. Thank you so much for talking me through this!
Seems weird to me, but it looks like the surface setting that controls the reflectivity is actually Metallicity (thanks, @Paintbox !). All of the other Reflectivity settings don't seem to do much in this setting.
I'm going to guess that HDRI alone is not going to be good enough. I just tried it using a character, the mirror, and one of DimensionTheory's Skies of iRadiance HDRIs. The reflection works well enough, but getting the lighting on the charater to work the way I'm picturing your description would be a real hassle. Also, if your scene is inside an enclosed room (almost has to be with mirrors, in my experience), the walls and ceiling will turn the whole room into a giant mass of shadows, just like natural light in a room with only a few windows. You'll probably need additional lights to get your look right. Try this:
https://www.deviantart.com/sickleyield/journal/Tutorial-Getting-Started-With-Iray-519725115
Epecially check out the section on meshlights in that tutorial. If you create meshlights that shine on or illuminate somehow at least the side of your model facing the mirror, or ideally light up the whole area, you should get the effect you're looking for. An added trick is to create primitives, like small planes, then set them up as meshlights. After that's set, put the Cutout Opacity setting down to around 0.00001 or some other extremely small, but non-zero, number. The light will still show, but the object will not. If you have spare cash or just want to wishlist them, see about picking up these:
https://www.daz3d.com/iray-ghost-light-kit
https://www.daz3d.com/iray-ghost-light-kit-2
They do everything the above can do, but it's a thousand times faster and easier. Also, I'm not sure why this was happening this time (never noticed it before), but using primitive planes was causing noise in the image. Fix: same process, but set Cutout Opacity to 1.0 and put a solid black jpeg as Cutout's Image Map. Same effect as above, no noise.
While it seems you have your mirror shader figured out, I wanted to add this. I found it in the foums a couple of years ago and it works great when I want a mirrored surface:
1. Select the mirror glass (or surface you want to be reflective) in the Surfaces tab
2. Apply the Iray Nickel Shader to the mirror surface
3. Change Glossy Reflectivity to 1.0
4. Change Glossy Roughness to 0.01
This should reflect like a mirror.
I wish I remembered where I found it so I could give credit.
Also, if you are using a HDRI for the light, you may be able to rotate the dome in order to get the character lit enough without additional lights. but that can be difficult because the ideal light would be in front of the character, and the mirror would block the light. As LosingSignal said, mesh lights would be best if you want supplemental lighting to better show the character. And I add my +1 to the ghost lights. They're great for adding fill lighting when using HDRIs if you dont want to (or can't) use a 3-point light rig. And they have quick settings for light temperature and luminosity.
if you use that shader I linked to then you won't have any lighting issues
@Szark - your link is to outside Daz and I have no idea how I'd go about installing that shader and whether it would be compatable :(( But thank you!! @losingsignal, i am willing to pay to save myself two hours of meddling, thank you!!! is Ghostlights basically a one click solution ? thank you for pointing me toward metalicty property too and the tutorial. Sigh. Just when I get the hang of one thing in Daz, i discover the next thing i wanna do takes 5 hours to learn :(( you guys rule for helping!
Download the shader to whereever you want on your hard drive and unzip.
Open Daz Studio go to where your Shaders are in the Content Library Pane (NOT SMART CONTENT) Normally Daz Studio Formats > Shader presets > Iray
The Right Click in the bottom part (where the Iray Shader thumbnails are) and chose the "Browse to File Location. That will open the Iray shader folder on your Hard Drive.
Alternatively Right Click on the Iray folder and choose the make a new Sub Folder, give it and name and OK. Then you can right click the new folder and Browse to that instead, to put new shaders in.
Then go and grab the Mirror shader (both the duf and png), select Copy and paste it in that content folder.
Go back to DS and right click on the shader thumbnail part of the pane again and choose to "Refresh".
You should now see the Mirror Shader.
The mirror prop already has a proper Iray mirror shader applied to it so you actually don't have to do anything with the shaders or surface. If you load the mirror prop and aren't getting the reflection, post your render and what you have in the scene.
Here is the mirror prop loaded with no modifications made to it.
well it is down to not having the right lighting after all as I can use a HDRI set to o.10 Intensity so it is very dark and I still get reflections.
You're welcome! Basically, yes, its a one-click solution. Actually more like four clicks, plus dragging and rotating the light into place, but yes, fast and easy.
Playng with Daz made me renew my library card just so I could check out books on photography and shot composition. Well, here's to never running out of things to learn...
No special magic about mirror shaders required. A white metal shader with little or no roughness will work as a mirror, like several of the ones included with DS in the Iray Uber shaders. HDRI's work fine too. In the attached image, the mirror is the polished aluminium and the HDRI is the stock default 'RuinsB-500' at default strength. As stated above, HDRIs will not illuminate a closed room - you will need some other light source.
OMG, RobotHatArt, Please please please walk me through how you did that?! I am getting a reflection now but I can't get the lighting right no matter what i do and you got it right off. Screenshots?? here is my work in progress... my reflection shadows make the girl look like a piggie... I've never been able to figure out a brightly lit interior like you just did. please show?
I just used the sun/sky to light the background. You can see the character's shadow cast in my render cast by the sun. Now this would leave the character in dark shadows in the reflection since they are facing away from the light source. To remediate this, I create a ghost light (https://www.daz3d.com/iray-ghost-light-kit) the size of the mirror and placed it in between the character and the mirror, with the light facing the character's face. The benefit of the ghost light is it doesn't show up in the mirror's reflection so you get the lighting without the glare or an odd floating white rectangle in the render. If you don't have the ghost light kit, you can make your own by creating a plane primitive, applying the Iray uber shader to it, set the emission color to white, set the luminance to higher value until it glows (but not overpowers the scene), then set the cutout opacity to a really small number like 0.0001.
@RobotHatArt, thank you so much!! i got the Ghost lights and followed your direction and i think i'm in business! I am not sure why i need to point the light at the character instead of the mirror to the get the reflection to light up, but it works (and doesn't work the other way). Super helpful!