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Creating Shape rules?


revnart

revnart

Power User
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I know its not a big problem, but maybe someone here knows the "rules" of this situation.

When I click on canvas with Rectangle Tool (U) a popup appears where I can input width and heigth of new rectangle.
but In example - I need 150cm wide one and I get error message:

" A value between 0,00 cm and 76,20 cm is required. *Closest value inserted."

but as far as I noticed - max size is changing depending on PPI.

examples which shows canvas size, max rectangle popup and PPI:

uploadfromtaptalk1436527261100.png
uploadfromtaptalk1436527366571.png
uploadfromtaptalk1436527378563.png
 
Before we go into this can you change your INFO panel to display 'Document Dimensions' instead of 'Document Sizes'...?

Then post another screen shot as above....we'll take it from there.

Regards.
MrToM.
 
OK...

I dont get this error in CC 2014 and you didn't say what version you are using so this will have to be a 'generic' reply.

By looking at the Document Dimensions can you now see why you get the error?

The document is only 29.69cm wide so there just isn't the room for a 150cm wide rectangle.

The Maximum width that will fit the document is therefore entered into the box for you.

In CC 2014 it ignores this and just creates the shape regardless.

ppi does play a big part in this but only in so far as PS uses it to convert user input into pixels...for eg, if you enter a value of ??.??cm PS has to convert that into pixels so that it can work with it.....digital images are after all defined by pixels, not linear measurement.

If you change the ppi then the result of converting to pixels obviously changes too resulting in different 'dimensions' although the actual amount of pixels doesn't change. As the 'dimensions' are different this sets the largest 'shape' size accordingly.

You'll probably find that lower ppi settings result in larger shape sizes and vise versa.....for eg a ppi of 1 would mean 1 pixel = 2.54cm.....with a document 1168px wide that means a document width of 2966cm....well bigger than the 150cm you require.

Going the other way if you set a ppi of say 600 then the width would be 600px = 2.54cm....for the same document size that would be only 4.9cm wide....no where near 150cm.

Is that what you wanted to know?
It wasn't really clear from your statements exactly what it was you were asking....sorry.

Regards.
MrToM.
 
Thank you for your response :) it brings some more light in that topic :) I was just confused because file with same dimensions in cm allows me to create bigger or smaller rectangle depending on ppi. Each time larger than canvas size. I will try something more when I get back home :) thanks once again :)

Wysłane z mojego SM-G360F przy użyciu Tapatalka
 
revnart said:
...I was just confused because file with same dimensions in cm allows me to create bigger or smaller rectangle depending on ppi...
Click to expand...
Well that cannot happen unless you are re-sampling the document....adding or removing pixels.

You have to appreciate that a digital image consists of pixels and has NO linear measurement such as cm, inches, miles, gigaparsecs whatever.

The dimensions you see, (in cm), are the PRINT size and are CALCULATED from the pixels AND the erroneously named dpi value.....it should read ppi.
As such, changing ANY one of those means that at least ONE of the others also has to change to compensate.

If you keep the number of PIXELS constant and change the PPI then its PRINT size also has to change.
If you keep the number of PIXELS constant and change the PRINT size then the PPI also has to change.

If you keep the PPI constant and change the PIXELS then the PRINT size has to change.
If you keep the PPI constant and change the PRINT size then the number of PIXELS has to change.

If you keep the PRINT size constant and change the PIXELS then the PPI also has to change.
If you keep the PRINT size constant and change the PPI then the number of PIXELS also has to change.

You see how it works?

Ideally when creating a new document you should already know if the document is to be finally printed.
You should therefore set up your document with that in mind and if so base all your parameters off the ppi setting....by either then...

1. Entering the number of PIXELS and have PS calculate the PRINT size....OR...
2. Enter the PRINT size and let PS calculate the number of PIXELS....this is the usual approach.

If OTOH you know for sure that the image is ONLY ever going to be displayed in a digital format, ie, on an lcd screen then you can ignore ppi altogether.....it makes no difference.

The exception to that is that you could use it to re-sample an image. This shouldn't happen with a new document as it should have been set up correctly but may be required if working on an existing document which was never intended for print.

Setting up the document correctly from the start should mean that you would never even attempt to create something bigger than the canvas you have to work on....you wouldn't try to draw an A3 image on an A4 piece of paper so why do it in PS?

Does that shed any more light?

Its a fairly simple concept but not an easy one to explain,......not concisely anyway....sorry.

Regards.
MrToM.
 
Last edited:
Thank you Tom :) I understand those rules :) everything now makes sense, I just found out that not the canvas size is the limit.. It's rectangle tool when creating from "click" is limited to 3000 pixels, this info plus everything you already wrote solves my problem :) thank you :)

Just for info: Photoshop CS6 on Mac
 
Last edited:
revnart said:
...limited to 3000 pixels...
Click to expand...
Interesting!

I wasn't aware of that, thanks.

I guess that's a limitation of either CS6 or Macs then as in CC 2014 on Windows there is no such limit.

Can you still 'transform' the shape larger though?
May as well just drag it out to the size you need then really.....I mean why do it twice? :bustagut:

Regards.
MrToM.
 
Once the shape is created there is no problem of setting new dimensions in options bar can't check right now is it has any limit but for sure much larger than 3000 pixels because that was my workaround :)

Wysłane z mojego SM-G360F przy użyciu Tapatalka
 
I just checked CS6 on Windows and yes, it does limit the typed values to 3000px......never noticed that before.

Anyway, at least we now know its a version issue and nothing more serious.

Thanks again.

Regards.
MrToM.
 
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