Creating billbaords?
kyoto kid
Posts: 41,052
...hopefully this is the right forum to ask this question.
I have a scene I'd like to create a specific city skyline billboard for. I have been able to convert the sky in the photo I'm using to an alpha channel but that is as far as I could get. Using a basic plane primitive as the backdrop will not work since it's diffuse colour will show behind the alpha channel portion of the photo. I have seen irregular shaped billboards for elements such as plants, smoke, flames, and crowds and wonder how are these made?
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This is more of a material/rendering question. Do you have a link to an image of what you want your scene to look like?
I think people usually take the photo with the alpha channel into Photoshop (or similar) select the alpha'd part and create an image with that area set to full black and the rest to full white, then load that BW image into the opacity/cutout channel (3Delight/Iray as appplcable).
...as mentioned I converted the sky to an alpha channel and saved as a .png. Where I am having issues is how to not have the sky part of the plane show up in the scene as there is no way to assign an alpha mask to something in the Daz programme
I posted this here because I would like to know how PAs like Jepe and DimensionTheory (Ecomantics) do it as a prop that you simply load into the scene.
You're going to need to use masking at some point. I'll have to look them up to see what kind of scene they are doing with Hexagon.
...oh yeah. forgot. Below are two different versions of the scene. The first with just the HDRI sky and one with the the full city skyline backdrop photo I wish to use with the HDRI.
Ok. So it's the same scene in each render, just with a different background. Hexagon has nothing to do with this. HDRI is handled in the renderer. You need to find a 360 degree photo of that town if you want to use it as a skydome HDRI, after converting the photo to HDRI.
One trick that some renderers can do is use both a backdrop image and an HDRI image at the same time. Just tell the renderer to not display the HDRI image in the render, but still use the lighting from the HDRI.
...don't have the gear or software to create my own HDRIs (or the funds to fly to Zagreb).
Also I would rather use the HDR sky in the first pic above rather than the one in the photo because it has depth. I also need the HDRI image for the reflective surface otherwise, no reflections.
I'm looking at how to make reusable billboard props like in these products:
https://www.daz3d.com/ecomantics-efficient-ecosystems
https://www.daz3d.com/now-crowd-billboards-modern-city-life
https://www.daz3d.com/cityscapes-backdrops
https://www.daz3d.com/jepes-flamez
If you have the Alpha channel set in the background .png then open it in the LIE and set Transparency to Alpha which should work.
The rendering gets pretty involved then, masking out the sky, masking out the reflections, then building the scene up in layers using a photo editor. I've downloaded HDRIs of city streets in the past for this kind of stuff. They don't have to be perfect if used just for reflections of buildings on things. One render just does it all then. No editing of images later.
...for the one scene figured out how to create the needed opacity mask of the city skyline (see below)
Still would like to know how make permanent billbaord props that could simply be loaded in like the products I linked to.
There's probably plenty of YouTube videos showing how to mask out cityscape images for setting their alphas to transparency on billboard textures applied to objects in rendered scenes. It's done the same way that leaf textures on tree models are made.
...it's one thng to do it on a scene by scene basis. I'm looking to create reusable billboards like the trees from Ecomantics. Don't those need some kind of supportive properly shaped flat mesh?
Carrara will model each leaf of a tree. But then not give the leaf a decent texture. So trees look plastic in a scene. I prefer leaves to be billboards, like how Vue and others do them.
Depends totally on which leaf object you assign to your tree.
Reusability has nothing to do with the billboard shape. All you need to do for reusability is set up the billboard and then save it to your library. There! Reusable!
Those billboard trees are shaped like that because it cuts down on the rendering time not to have large transparent areas, as well as helping avoid major global illumination artifacts.
...so OK I have a number of city skyline photos I like. I want to make them into billboards to use in future scenes (like the curved billboards in the Cityscape Backdrops). There is no way in the Daz programme to create a curved plane primitive, so it sounds like something which needs to be done with teh aid a modellig programme. This means not only including the diffuse image but also the opacity mask as part of the item to automatically be placed in the proper channels when loaded. Agreed that one wants to keep the transparency region as small as possible to minimise the impact on rendering time and the issue of artefacts.
What I am trying to get at how does one make this as an item to install in your Runtime/Library so that it can be loaded with one click like any other content like the commercial products in the links above?
So you can't create a cylinder, select the faces you want in the geometry editor and delete the rest then? This is very weird because those tools are included in the current version of DS by default.
And no, creating a curved billboard in an external modeling program does NOT mean any of that. It just means you have to import it first. After that, the setting up of textures and alpha maps is the same regardless of the origin. As is saving it to your library. And after ten years active here you should know by now how to save a scene or object to your library.
...or package it like a freebie/product that can be installed directly in the runtime with proper icons and material selection (3DL/Iray). That is what I am looking at doing. I don't have to set up the opacity maps each time I use one of Jepe's or DimensionTheory's billbaords.
Then how about you load it from your library? That's the whole point to set it up and saved it to your library in the first place.
..partly because I have a categorised runtime setup with "environments" as one of the folders. Partly because it would be the first exercise in packaging content properly..
So you don't just want to have it available for re-use, you want to package it as aproduct for sale/freebie? Why didn't you say so in the first place?
The Documentation Center has a step-by-step guide on packaging your content
...that would be the long term (freebie).
I would think that backing it a photo with an actual curved or flat mesh that is properly scaled would be superior than just using a Daz primitive. Making a curved plane in Hexagon sounds a lot less tedious than using the geometry editor in Daz on a large diameter cylinder primitive, as the supportive mesh needs to be as smooth as possible which with the geometry editor means deleting a lot of polys by hand.
Or you just add a SubD Modifier to the low-poly object.
But that's beside the point. Yes, doing it in Hexagon is quicker and easier. But you claimed it cannot be done within DAZ Studio when it can (regardless how convoluted the workflow is in there it is NOT impossible),
And setting the object up with textures and alpha maps is still a task that is to be done after import to DAZ Studio. All you need to do in Hexagon in that regard is make sure you've got a working UV mapping on it.