Print at Sep 23, 2018 11:09:32 PM View all posts in this thread on one page
Posted by Pixelwizard at Feb 27, 2017 12:41:11 PM
Background Image wrong Scaling
i just discoverd an issue...it's very irritating. actually i rebuild a skyscraper ;) i have a very good floorplan and other informations to create a very precise construction. but the scaling of the imported background-picture ist wrong. while the x-dimension is almost perfect, the y-dimension does not fit in anyway. i checked the image with photoshop and did some measurements. the base layout of the building and plan is a square - so it should be easy. any distance measured in ps is fine and identical where it must be. could it be that for some reason the dpi's of the floorplan cause this issue? actually th jpg has 200dpi - should i increase to 300 or decrease to 72dpi? or 96dpi? i can work for the outer elements just by creating groups, copy, paste and turn. but the inner structure will be hard to create this way...especially because there are some levels with the same core but a different layout.
any ideas?
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WIN10 Pro 64bit * 16 GB RAM * AMD FX 6100 * Geforce GTX 660


Posted by Puybaret at Feb 27, 2017 8:22:43 PM
Re: Background Image wrong Scaling
I don't thin that changing the dpi will resolve your issue.
Is the apparent width / height ratio you plan, simply measured with a ruler on the screen, really different in Sweet Home 3D and ps or other image program?
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Emmanuel Puybaret, Sweet Home 3D developer

Posted by Pixelwizard at Feb 28, 2017 4:06:35 PM
Re: Background Image wrong Scaling
there is (for some reason) a difference. but it seems, there is a way to minimize it. the bulding has a lot of colums, surrounding a square. so any x and y coordinate is well known. in ps i can create a ruler with my own scale. if i measure in ps, i find for any distance i measured the same value, corresponding to the calculated x/y coordinates. what i did was to refine the scaling during import of the background image. they more precise the start- and endpoints are set, they more precise the background fits to the plan. accepting the plan inside has tolerances, i just keep my eyes to the four important outer edges. i minimized the difference from approx. 45 cm in y to 10 cm in y now.
i still guess, this is a effect calculating a jpg from 25 cm to 41 meters... i have a "little ,)" experience with calculating pixels and resolutions, so i keep it in mind and will do some tests with higher resolution of the basic plan to find the key which values will give the best possible result. it's like some effects in prepress - just think of the effects of posterisizing if you push a small, low resolution icon to a lot bigger size. you will loose the precision in any way. helpful could be to know, which "resolution" is used in the program to draw all the lines. then it's possible to calculate backwards, to get the correct resolution for a bitmap (jpg is a bitmap) in the beginning to fit to the final resolution after scaling up. sounds complicated, but this calculation is used since years in prepress when you scan lineart. they more you have to scale it up at the end to a target resolution, they more scan-resolution you need in the beginning to compensate "unsharpness".
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WIN10 Pro 64bit * 16 GB RAM * AMD FX 6100 * Geforce GTX 660