Author Topic: Image size  (Read 723 times)

Offline archonforest

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Image size
« on: February 15, 2018, 09:39:28 AM »
If I want to use an image map in TG to cover for example a 1 by 1 km square, what size of document I have to set up in Photoshop?
Is there a way to calculate this?

Offline Hannes

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Re: Image size
« Reply #1 on: February 15, 2018, 10:39:15 AM »
I guess you don't have to create a certain size in PS. This texture should be as hi res as possible. In TG you can adjust the size so that it covers the 1km area you want.

Offline luvsmuzik

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Re: Image size
« Reply #2 on: February 15, 2018, 10:50:29 AM »
There used to be a graduated scenerio of 128x128, 256x256, 512x512, 1024x1024.......

I never knew either if that was in relation to quality (which I suspect) or a magic size to cover an object (1m cube), a square meter geographically....

I think the important element would be to make your texture tilable so that if you have to scale with repeating x or y it blends rather than have obvious mismatched seams. Photoshop should have a built in function for that.

Offline archonforest

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Re: Image size
« Reply #3 on: February 15, 2018, 12:03:53 PM »
Thx for the answer.
I was not looking to texture but draw a river and use that. I tried this technique before and after importing into TG the image was a bit small. But if I made the image bigger in TG then the river got also bigger plus the PF that was masking the area around the river was blurry in the rendering... hmmm....this is the reason I was asking this question. Guess will have to do more test with different image size...

Offline Hannes

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Re: Image size
« Reply #4 on: February 15, 2018, 12:11:43 PM »
Why not making a orthographic render of the area you want to put your river in? Then you can take this as reference in PS (scale the whole thing up to a very good resolution) and paint your river.
You can then either rescale the image in TG until it covers your area or you could even use the camera you made the ortho render with and project it onto the landscape via camera projection.
« Last Edit: February 15, 2018, 02:08:08 PM by Hannes »

Offline archonforest

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Re: Image size
« Reply #5 on: February 15, 2018, 12:47:46 PM »
Thx! :)

Offline N-drju

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Re: Image size
« Reply #6 on: February 15, 2018, 03:39:44 PM »
Isn't it possible to just use the "make river" operator or something with similar name? I'm not sure if it fits your expectations, but it sure was possible to carve the riverbed this way.
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Offline Oshyan

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Re: Image size
« Reply #7 on: February 15, 2018, 09:42:07 PM »
Think of the level of accuracy you want. Let's say you know you want to create specific features within a 1000x1000 meter area (1km square). If you make an image that is 1000 pixels on each side, then you will have "1 meter per pixel" accuracy. Each pixel will represent 1 meter. Now let's say you want your river to be 10 meters across. That means your river can *only* be 10 pixels wide in the image you create! It also means that if in some places the river you paint in the image is just 1 pixel wider, it will be a full 1 meter (~3 feet) wider. In a close-up scene that could be quite noticeable.

So there is no simple, single answer, it really depends on your goals. But thinking in terms of pixels-per-meter can be very helpful. It gives you a real-world reference for how much accuracy/specificity you're going to be able to get in creating and using your image, and should help you determine if you need more resolution.

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Offline archonforest

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Re: Image size
« Reply #8 on: February 16, 2018, 06:53:56 AM »
Think of the level of accuracy you want. Let's say you know you want to create specific features within a 1000x1000 meter area (1km square). If you make an image that is 1000 pixels on each side, then you will have "1 meter per pixel" accuracy. Each pixel will represent 1 meter. Now let's say you want your river to be 10 meters across. That means your river can *only* be 10 pixels wide in the image you create! It also means that if in some places the river you paint in the image is just 1 pixel wider, it will be a full 1 meter (~3 feet) wider. In a close-up scene that could be quite noticeable.

So there is no simple, single answer, it really depends on your goals. But thinking in terms of pixels-per-meter can be very helpful. It gives you a real-world reference for how much accuracy/specificity you're going to be able to get in creating and using your image, and should help you determine if you need more resolution.

- Oshyan

Tku Oshyan! Very usefull data. :)

Offline Dune

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Re: Image size
« Reply #9 on: February 16, 2018, 07:09:58 AM »
I use maps all the time, and for an area of say 2x2k I tend to make a base TIFF of 4x4k (grey). I use scales that are set from the start, depending on what the area specifics are. What Oshyan says; it depends on the level of accuracy you need. My smallest paths are sometimes only 1-2px wide, but sometimes fall away. I always test the width I draw roads/paths waterways first and measure them in TG. Say I paint a line with a 12px soft brush, and the line in TG is 5m wide, and I need a path 2m wide, I can do 2 things, reduce brush to 6px or so, or adjust in TG by color adjust. I use a mix of both, just depends on what I need.
But greyscale 8 bits is fine (and not heavy at all), and you can combine 3 grey maps in one RGB file, split again in TG.

Offline ajcgi

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Re: Image size
« Reply #10 on: February 16, 2018, 09:04:10 AM »
There used to be a graduated scenerio of 128x128, 256x256, 512x512, 1024x1024.......

I never knew either if that was in relation to quality (which I suspect) or a magic size to cover an object (1m cube), a square meter geographically....

I think the important element would be to make your texture tilable so that if you have to scale with repeating x or y it blends rather than have obvious mismatched seams. Photoshop should have a built in function for that.

I'd imagine that was more to do with the processing efficiency from working with binary processing on base 2 image sizes. My textures for work are almost always one of these sizes unless my hand is forced another way. These days machines are so outrageously fast that I'd be surprised if there's any advantage now.

Offline archonforest

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Re: Image size
« Reply #11 on: February 16, 2018, 10:20:57 AM »
I use maps all the time, and for an area of say 2x2k I tend to make a base TIFF of 4x4k (grey). I use scales that are set from the start, depending on what the area specifics are. What Oshyan says; it depends on the level of accuracy you need. My smallest paths are sometimes only 1-2px wide, but sometimes fall away. I always test the width I draw roads/paths waterways first and measure them in TG. Say I paint a line with a 12px soft brush, and the line in TG is 5m wide, and I need a path 2m wide, I can do 2 things, reduce brush to 6px or so, or adjust in TG by color adjust. I use a mix of both, just depends on what I need.
But greyscale 8 bits is fine (and not heavy at all), and you can combine 3 grey maps in one RGB file, split again in TG.

Tku! Great data here. 8)