Greenscreen > how its done !

[islandmon]

Check this video tutorial ...showing greenscreen & image prop techniques.

Greenscreen > how to do it !

[Kevin McAllister]

Cool link. Thanks for sharing it.

Kevin

[Assemblage]

Is there anywhere to go to understand steps for using VW for compositing? We want to export a model view with a transparent background for dropping into a photo for example. There must be loads of people wanting to do this, but I can't find much help on it.

Edited August 29, 2010 by Assemblage

[willofmaine]

If I understand your question correctly, it sounds like you may want to use a RenderWorks Background. This would include your photo in the Viewport when VW renders the model. This can make for better edges between the model itself and the background (photo) than might be achieved cropping and pasting the model into the photo with Photoshop.

Note that (at least in VW 2008) sizing RW Image Backgrounds can be kinda tricky. The online Help talks about their dimensions as being set in Page Units. This is a bit misleading...

Think of a RW Image Background as having a 'Real World' size (this is good because it means that when you change the scale of a Viewport, the background, sharing the same 'Real World' size as your model, will retain its correct size relative to your model).

So, if you have a 1/4" scale Viewport that is 10 inches wide, it represents a 'Real World' size of 40 feet (at the picture plane where, for all intents and purposes, the RW Background is located). Expressed as 'Page Units' (inches instead of feet-and-inches) its size is 40 feet x 12 inches = 480.

Unfortunately, if you're working on a Sheet Layer and you go to create a RW Image Background, the default size of imported photos seems to be about 11 inches wide; pretty close to what must be a common Viewport size of 10 inches wide. All in 'Page Unit.' But unless you significantly increase the Background's width, such as to 480 in this case, your Background will be a tiny image most likely hidden behind your model.

Put another way:

If you're on a DESIGN LAYER and you edit your RW Image Background, it will be expressed in inches as a function of the scale of that design layer. For example, if your design layer is at 1/4" scale, the background's width will be shown as 10 (1/48 of 40 feet = 10 inches...). If the scale of your design layer is 1/2", the background's width will be shown as 20.

If you're on a SHEET LAYER and you edit your RW Image Background, it will be expressed in inches as a function of its 'Real World' size, such as 480 inches (regardless of the scale of your Viewport).

Phew... the intuitive UI of VW...

[Assemblage]

That's helpful thanks - I'll try those.

There must also be a way with the transparency. I gather it involves using image masks and transparency shaders. But I'm struggling, and assume there are familiar steps to advanced users.

[Horst M.]

For my Point of View it is more promissing (and less painfull) using a plain green background in RW and doing the composting with the Green- or Bluescreen Technology that islandmons link on the top of this thread demonstrates.

There was recently a thread related to this:

http://techboard.vectorworks.net/ubbthreads.php?ubb=showflat&Number=142850&Searchpage=1&Main=24880&Words=background&Search=true#Post142850

unfortunately the linked example seem to be gone.

Edited August 29, 2010 by Horst M.

[Matt Panzer]

Hi Assemblage,

Not to toot my own horn, but CameraMatch may do what you're asking:

[Kim]

If you render your model with a plain colour background then export it as an image file it is then an easy step in Pixelmator or Photoshop to remove the background and place the model on a photo. Using the editing tools will create an almost seamless finished view, as long as you have your perspective right on the model.

[Jonathan Pickup]

wouldn't it just be quicker to use camera match?

[Assemblage]

Thanks Matt P this is useful. The masking tool in CameraMatch seems to work a bit like Photoshop's Background Eraser tool which is what we currently use.

The traditional division between 'presentation' work and design development is fast collapsing. We/clients/others need to see ongoing design work 'insitu'.

Given png supports alpha, why in VW is there not simply a check-box when exporting for "Render background as transparent"?? These pngs could then be dynamically linked to a layered Photoshop file which automatically updates. Scribing outlines each time a rendering is done is swimming against the tide in my opinion.

[Matt Panzer]

No problem Assemblage,

It would be nice to have VW export images with transparent backgrounds. It does sound like CameraMatch could help with the situation since it could already have the background photo in the image (and greatly helps to align the view). It all depends on what exactly you're doing.

Matt

Edited September 1, 2010 by Matt Panzer

[Assemblage]

Will stick it on the Wish List..

[Assemblage]

Matt, do you have a time frame for releasing CameraMatch for VW2011?

[Matt Panzer]

Assemblage,

<--place usual software developer response to upcoming releases here-->

With the above said, you shouldn't have to wait very long. :-)

[Billyy L]

For my Point of View it is more promissing (and less painfull) using a plain green background in RW and doing the composting with the Green- or Bluescreen Technology that islandmons link on the top of this thread demonstrates.

There was recently a thread related to this:

http://techboard.vectorworks.net/ubbthreads.php?ubb=showflat&Number=142850&Searchpage=1&Main=24880&Words=background&Search=true#Post142850

unfortunately the linked example seem to be gone.

Such a very amazing link!