Nov
13

Cut-out people in a Blender archviz scene

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Whether your scene could use them for a bit of extra detail and realism or just because the client requested it – you have to be prepared to insert them: the happy, carefree cutout people 🙂 (yes, they are usually smiling)

People can be added to the images in two ways, the easiest and most popular way seems to be in post processing (PS, Gimp), but there are advantages as well to inserting them in the Blender model as planes with transparency.

What would be the pros and cons of adding cutouts as planes in Blender? There is an obvious need to do that for animations. In still images, using planes makes scaling the people to real size easy, while in post editing you can make a muddle if you are in a hurry. You can get shadows and reflections without the pain of making them up in Gimp. Of course, if the orientations are wrong you can also get bad give-away shadows and reflections of your 2d-tricky-person. One thing I appreciate is the shortening of the work flow. Having to change something like the angle or render size after you have already prepared your 10-15 people layers means you’ll also lose some time fixing this against the change, while planes in the model will not require fixing – maybe just moving them around a bit. You can also get them to pop out from behind other objects versus making masks in post processing. There is one thing post processing is better at: blending the people in with the scene and applying filters if needed. But still, the tenacious Blender user can use render layers and Compositor to this purpose.

There is also the odd case in which the client does not like the blond girl in the foreground and asks you to remove her right before deadline. Having her on a layer in Gimp solves this faster.

Inserting people as planes is a breeze since Blender got the wonderful “images as planes” addon. First you have to make sure the images you use do have an alpha channel. Then you can adjust the settings in the import window panel or later in the material and texture panels.

Some variations on the settings are possible, for instance I use shadeless and a bit of emit on the material texture when I want the cutouts to look brighter (and happier 🙂 ). One important setting not to be missed is “premultiply” in the texture->image tab, not having it checked results in some bad white edges around the alpha areas.

The scene in the image above:

One last neat trick is to link your cutouts to the camera, so they automatically face it (concealing the billboard trick) and keep facing it when you move the camera around:

It kind of looks like kites! Then you have to creatively solve the issue of using several cameras and reattaching all “kites” to the new point of view without too much trouble. In this one I had just one camera and several positions marked with empties, then I moved the camera between them, snapping with Shift+S options. Maybe there’s a better way, like renaming cameras, or setting up a different layer of cutout people for each camera?

Later edit: best fix found for reattaching cutouts to a different camera: I attached them to an Empty object, then I can snap the Empty to the position of any of the cameras. This way I can also make a library file with cutouts ready scaled and linked to an Empty and append them to my scene, ready to use.

Hope this has been useful, happy blending everyone!

Note: the featured image is a BI render with some post editing (hence the exagerated glow)

 

 

 

  • Great idea tracking them to face the camera and using empties to snap the camera too. You have the best camera ideas.

  • Warcos

    wow … is an interesting solution ..

    thanks

  • rudl

    nice 🙂

    I always struggle to find good free and smiling cutput people with working alpha chanel.

    Do you wan’t to share the source?

  • Oana

    Hi! I’m writing a sequel to the post, including a sources list

  • I there great idea i never thought use the plug-in image like planes in that way!! But with the camera you can use key frames.
    configure one camera in frame 1 an then move to frame 2 and set another location for the camera ten insert key frame.
    In that way is good for rendering over night, in the other day you have all your cameras rendered..
    But i am shore you already know this…
    Best regards!

  • Oana

    NOPE! That’s the best idea ever and it did not cross my mind, thanks Ricardo 🙂 I’m not so used to animation that’s why I never thought about using keyframes. I guess turning layers and lights on/off could also be keyframed, I’ll have to try it in my current project.

  • RudyD

    You can apply an texture as image to a SVG(curve object) in blender, and make an exact cutout of a person or other object, it’s not really 3d but its the same as image as plane application. Curves on a flat plane(cutout fashion) can be done by editing the image in blender, adding an alpha channel, if one does not exist for the image format, and saving the image as PNG. I create lots of cutout diorama type scenes in blender this way, and Gimp’s path from selection is great for tracing any image that has the background removed by deleting the background and leaving it completely transparent. Simply load the image into Gimp, apply an alpha channel, delete any background areas to leave transparent pixels, and use the select by value tool in gimp to select all the transparent pixels, invert the selection to create a Path from the selection that matches the exact outline of the image, and export the path as an SVG file. Import the SVG into blender and apply the same image that you use to create the Path(Exported as SVG from Gimp) i.e. Image saved as PNG(Or any other image format the preserves the alpha channel data). It’s very easy to import the SVG as a curve object in blender, and apply the PNG as a texture to the SVG curve object. once this is done you have a exact cutout and the shadows will be exactly the shape of the curves and inner regions of the cutout, unlike planes that show on square or rectangular shadows. It beats the hell out of doing all the layering and Chroma keying, and Chroma Keying will not cast the proper shadows over a 3d scene, the way cutouts do, the only thing better than this method, and actually using 3d object for all the people and objects in a isometric/3d scene render. Those cutouts if properly lighted and with the proper materials attached to the curve object, and almost appear to be 3d, but they are actually just cutouts with images applied. Actual cutouts and not simply planes with transparent pixels.

    Please note that this method works fine in Blender 2.68a, but in late versions the texture space does not work properly with curves and images as textures applied to blender curve objects.

  • RudyD

    edit: Curves on a flat plane(cutout fashion) can be done by editing the image in blender,

    to:Curves on a flat plane(cutout fashion) can be done by editing the image in Gimp,