How do you do rotoscoping in Blender?
I’ve seen some clips on youtube that have used blender but i want to know how they did it.
as in, getting the video in and such
make shape keys for a mesh or 2D curve by tracing key outlines of a video. see http://wiki.blender.org/index.php/Manual for animation->shape keys.
How do you get video into blender in the first place?
select the camera , then choose in the viewpoert : view , then choose : background image -load - use - autorefresh.
then each frame you must copie what u want. wheather its a shape or a movement.
You can do this in Blender directly in a UV/Image editor window via the paint tool also. You only need to use the 3D window if you need to use curves (with hooks, etc…) or other actively deformed geometry as masks. Unless you have the dexterity of a Bridgeport mill then you’ll probably need a Wacom or other tablet because a mouse just won’t cut it for tasks that aren’t of the quick ndirty nature.
Load an image or movie into a UV/Image editor via the window’s header, Image>Open (ALT + O for keyboard shortcut) then with your mouse over the window press Nkey to bring up the Properties widget or use View>Properties. If you loaded a sequence then enable the “Auto Refresh” button on the properties window and enter the number of frames in the sequence in the “Frames:” field of the widget. Now open an Image Paint widget with Ckey or View>Paint Tool. Enable the little Brush icon on the window’s header (the one next to the image name/datablock popup – which will allow you to paint on the image in the window). Create a brush and start rotoscoping away. You can use procedural textures to paint with also which is kinda neat (you must create them via geometry and the 3D window first).
At this time image painting still only supports one level of undo so if you make 2 mistakes in a row without correcting then you may be screwed (unless it’s with an Add Alpha or Erase Alpha brush, – keeping a separate copy of your images is always a good idea). When you finish one image of the sequence and want to go to the next just use the arrow keys (as long as you enabled Auto Refresh).
When you’re finished painting use the window’s header to Image>Save Changed Images to overwrite the files that you pulled from. If you forget this step then all of your work gets lost. When painting on sequences Blender is limited to available system memory (RAM) so you may be well advised to only load several frames at a time if they’re high def or 32BPC HDR such as OpenExr files (Blender can paint on multilayer exr files but it can’t save multilayer sequences so you’ll have to do them one at a time if you’re into that brand of masochistic release.
When saving the image for the drawing mask, does it save both the background and the mask, or only the mask?
Is there a way to save only the mask(white part) of the image when painting it? It would be nice to have an alpha background as well. I tried saving, but it just is like i painted directly onto the image. Any way to make another layer or something so that I paint on that layer and not on the image?
Thanks.
Yes. Just be sure the image or sequence is loaded into the compositor and connect it’s alpha channel to a “File Output” node. As you advance frames each one should be auto saved to the file output’s directory.
Ok, thanks for that.
Can you keep the alpha when you render. I’ve tired saving as png files with RGBA set, but it doesn’t seem like its working.
It works fine, but .png from Blender is only 8 Bits per channel which is not all that great. You’d be better off saving to a format like OpenExr with the “Half” button selected. 8 bpc images tend to show major banding when any type of adjustments are made to them.
Everything you have described works fine for me up to this point. I’ve tried using tga and png but I just get white images.
What I would like to be able to do is to paint in say, red over a person in a video, then save the moving red character as a separate animation. All I can get is the video saved together with the red character over it. I could use chroma or difference keys to extra the red animation character but is there a way to do it directly please ?
Many thanks for any help.
You might also consider trying Claxa (www.patchmaker.net) It’s a freeware tool that is designed to automate the rotoscoping process. It takes awhile to get on to how to use it effectively, but it can save a lot of time in some situations.
Solved using “Erase alpha” ink.
On my tutorials page, you will find a complete blend setup , ready to use for garbage painting and Rotoscoping, and a PDF tutorial.