Video Screen Measurements/quartz world measurements

digitalgigalow's picture

MATH QUESTION:

Screen Size:

100 inches diagonal 49.5 inches high 87 inches wide

Objects/Props Size:

49.5 inches tall 12 inches wide 12 inches Depth

Here is the plan and question. I want to put the objects on the outer edge of the screen to project on them. they will be in two positions for testing. one will be 90 degrees flat face front, and the second will be 45 degree angle corner front. For presentation purposes both will be at the same position.

Question: what are the measurements of the real world screen compared to the Quartz world.

Example: In Blender 2.5, each square inside the 3D world equals 1 meter in the REAL world.

Is there a smart mathematician in here that can maybe help me?

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Scratchpole's picture
Re: Video Screen Measurements/quartz world measurements

I think your question might be irrelevant. The more important issue to consider is what projector and lens you will be using.

digitalgigalow's picture
Re: Video Screen Measurements/quartz world measurements

I do not understand your reply, but would like to know your reasoning. I do not understand what the projector and lens has to do with the screen dimensions.

here is the projector i am using:

http://www.epson.com/cgi-bin/Store/jsp/Product.do?BV_UseBVCookie=yes&sku...

thanx for the reply and your knowledge.

franz's picture
Re: Video Screen Measurements/quartz world measurements

QC dimensions are in ...QCunits ...Width is always 2, from -1 to 1.

If your screen is 87 inches wide, 1 inch is 2/87 QCunit. If your output resolution is 1024x768, 1 inch is 1024/87 pixels.

So 1 inch = 11.77 pixels = 0.0229 QCunit. (with your setup)

No need to be a Knight of the Lambda Calculus.

dust's picture
Re: Video Screen Measurements/quartz world measurements

(edit) noticed franz answered this in inches for you as well.

you can calculate real world units from pixel info, supposing you have an object with a known a size to reference from. actually you can do this without knowing a reference as well. for instance scientists can calculate the size of star via its density from a telescope but the lens most defiantly does apply. for maybe what you want you can use your viewer size.

lets say your screen size width is 1024 pixels at a resolution of 28.346 pixels/cm or 72 pixels/inch. your real world width in cm for 1024 pixels would be 36.124

to calculate pixels to units you would take your qc unit screen size of 2. thats -1 to 1 on x = 2 then divide that by your pixels width 1024 then multiply that by the pixel size your trying to get units for. in this case its 1024. this is handy if you want to convert mouse pixel coords to qc units.

it would look like this. (width/pixelWidth)*pixel

if you need this info in the qc world a width of 2 will = 36.124 so if you divide that by 2 then your size for 512 pixels in real world be 18.062 cm.

so if you where to print your image that is size 512 pixels at a resolution of 28.346 cm/pixels your print would be 18.062cm in real world size.

so if you want to calibrate you would want to use these figures and a pattern to make sure your projecting to real world size. make a square 512 pixels print it to 18.062 tape it to the wall then line up your projection.