Hello everyone,

I'm trying to generate a rendering from the following command:

rpict -x 786 -y 576 -ab 4 -ad 1024 -vtv -vp 14.636 -5.376 4.226 -vd

-14.504 13.433 -4.304 -vu 0 0 1 -vh 35.0 -vv 35.0 -vo 0 -va 0 -vs 0

-vl 0 -bv-

However, the pic file generated is in size 576x576. Could anyone tell

why Radiance did this? Thanks.

Yu Sheng

Hi,

You have a rectangle image description when specifying your -x and -y

values but your -vh and -vv values describe a square image. I think you

just need to delete your -y variable and you should then get a square

image. If you want a rectangle image then find the ratio between your

-x and -y value and apply the same ratio between your -vh and -vv

values.

I hope that makes sense.

Andrew

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-----Original Message-----

From: [email protected]

[mailto:[email protected]] On Behalf Of Sheng

Yu

Sent: 03 December 2008 16:47

To: [email protected]

Subject: [Radiance-general] Questions about image size

Hello everyone,

I'm trying to generate a rendering from the following command:

rpict -x 786 -y 576 -ab 4 -ad 1024 -vtv -vp 14.636 -5.376 4.226 -vd

-14.504 13.433 -4.304 -vu 0 0 1 -vh 35.0 -vv 35.0 -vo 0 -va 0 -vs 0

-vl 0 -bv-

However, the pic file generated is in size 576x576. Could anyone tell

why Radiance did this? Thanks.

Yu Sheng

_______________________________________________

Radiance-general mailing list

[email protected]

http://www.radiance-online.org/mailman/listinfo/radiance-general

Good start, but the formula is just a little more complicated for perspective (-vtv) views. See:

http://radsite.lbl.gov/radiance/digests_html/v2n7.html#VIEW_ANGLES

-Greg

## ···

From: "Bissell, Andrew" <[email protected]>

Date: December 3, 2008 8:53:07 AM PST

Hi,

You have a rectangle image description when specifying your -x and -y

values but your -vh and -vv values describe a square image. I think you

just need to delete your -y variable and you should then get a square

image. If you want a rectangle image then find the ratio between your

-x and -y value and apply the same ratio between your -vh and -vv

values.

I hope that makes sense.

Andrew

-----Original Message-----

[mailto:[email protected]] On Behalf Of Sheng

Yu

Sent: 03 December 2008 16:47

Hello everyone,

I'm trying to generate a rendering from the following command:

rpict -x 786 -y 576 -ab 4 -ad 1024 -vtv -vp 14.636 -5.376 4.226 -vd

-14.504 13.433 -4.304 -vu 0 0 1 -vh 35.0 -vv 35.0 -vo 0 -va 0 -vs 0

-vl 0 -bv-

However, the pic file generated is in size 576x576. Could anyone tell

why Radiance did this? Thanks.

Yu Sheng

Hi Yu Sheng,

As Andrew pointed out, you need to calculate the correct -vh and -vv values for your "camera" as well. Calculating the ratio of the image dimensions and simply apply these on the -vv and -vh values is not the best solution, however. There has been a discussion about this topic on radiance-online.org. Please also have a look at the attachment, which "implements" this discussion in a little tool that will calculate the correct vertical view angle, when a horizontal view angle and the image dimensions are given. I hope this makes sense to you.

-Iebele

Sheng Yu wrote:

viewsize.cpp (873 Bytes)

## ···

Hello everyone,

I'm trying to generate a rendering from the following command:

rpict -x 786 -y 576 -ab 4 -ad 1024 -vtv -vp 14.636 -5.376 4.226 -vd

-14.504 13.433 -4.304 -vu 0 0 1 -vh 35.0 -vv 35.0 -vo 0 -va 0 -vs 0

-vl 0 -bv-

However, the pic file generated is in size 576x576. Could anyone tell

why Radiance did this? Thanks.

Yu Sheng

_______________________________________________

Radiance-general mailing list

[email protected]

http://www.radiance-online.org/mailman/listinfo/radiance-general

Also keep in mind that you should be able to let rpict size your image

according to the view to fit within the x and y dimensions given. If you

know that you want an image 786 pixels wide, with any arbitrary

horizontal and vertical view angles, you could use options like:

-x 786 -y 10000 -vh [anglex] -vv [angley]

where the values in brackets are whatever view angles you want. This

will fit the image to the horizontal and allow the image to be whatever

vertical size it takes to meet your view angle parameters (in this case

with a cap of 10000 pixels). This works based on the default pixel

aspect of -pa 1. This way if the vh and vv are equal, it generates a

square, otherwise it will make an appropriately sized rectangular image.

## ···

-----Original Message-----

From: [email protected]

[mailto:[email protected]] On Behalf Of Greg

Ward

Sent: Wednesday, December 03, 2008 12:16 PM

To: Radiance general discussion

Subject: Re: [Radiance-general] Questions about image size

Good start, but the formula is just a little more complicated for

perspective (-vtv) views. See:

http://radsite.lbl.gov/radiance/digests_html/v2n7.html#VIEW_ANGLES

-Greg

From: "Bissell, Andrew" <[email protected]>

Date: December 3, 2008 8:53:07 AM PST

Hi,

You have a rectangle image description when specifying your -x and -y

values but your -vh and -vv values describe a square image. I think

you just need to delete your -y variable and you should then get a

square image. If you want a rectangle image then find the ratio

between your -x and -y value and apply the same ratio between your -vh

and -vv values.

I hope that makes sense.

Andrew

-----Original Message-----

[mailto:[email protected]] On Behalf Of

Sheng Yu

Sent: 03 December 2008 16:47

Hello everyone,

I'm trying to generate a rendering from the following command:

rpict -x 786 -y 576 -ab 4 -ad 1024 -vtv -vp 14.636 -5.376 4.226 -vd

-14.504 13.433 -4.304 -vu 0 0 1 -vh 35.0 -vv 35.0 -vo 0 -va 0 -vs 0

-vl 0 -bv-

However, the pic file generated is in size 576x576. Could anyone tell

why Radiance did this? Thanks.

Yu Sheng

_______________________________________________

Radiance-general mailing list

[email protected]

http://www.radiance-online.org/mailman/listinfo/radiance-general

____________________________________________________________

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