Basic concepts of Styles
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In SketchUp v6 we have two fundamentally different ways to have edges rendered. By default, vector (mathmatically defined by SketchUp's program code) edges are applied. Up until version six those vector edges were the only choice. With version six came a new technology that SU's developers call 'Sketchy Edges'. With them the edges may or may not actually be sketchy and that adds to the confusion. What 'Sketchy Edges' is all about is having edges defined not by vectors but by bitmapped sets of images. The program will in effect use a image of line (and that image can be "sketchy" or not) and use it to display an edge. The system is smart enough to be able to use sets of images showing lines of different lengths and apply them to the image appropriately enough that short edges get displayed with short images and with enough variation that the end effect can really look like it was, say, hand drawn.
SketchUp v6 uses the concept of "Styles" as a way to apply edge and other display-related effects. It is important to understand that the Styles are just a way to allow us to bundle together, reuse, and share particular sets of settings. An individual Style definition may or may not use the image-based 'Sketchy Edge' system. Some are defined with the default vector edges.
Now just to be clear, understand that when vector-based edge display systems are used the approach is really resolution independant as far as the program is concerned. It simply draws lines from endpoint to endpoint. In contrast the 'Sketchy Edge' system is very resolution dependant. Within a Style that has the Sketchy Edges, a set of 'line' images is used. If that particular Style incorporates 15 different 'line' images in it, then the program must render the visible edges in model view using just those images. SketchUp's system for doing that is actually quite sophisticated. It will shrink and stretch those images automatically and generally try to apply the most appropriate image from the set for a particular edge. Now of course it can't actually see the images and so all of this is done automatically using algorithms in the program code.
There are limitations to the system. The big one relates to resolutions. It makes achieving WYSIWYG (what-you-see-is-what-you-get) output difficult. An important aspect to understand is that what you see on your monitor has been processed by your graphics card while what you export doesn't use the graphics card at all -- exports are generated by the SketchUp software. Many users have a tendency when they export an image to assume higher resolution is better and so they crank up the pixel size of their exports using SU's export options. When the 'Sketchy Edge' system is involved the results stop being wysiwyg. The higher resolution means the algorithms are recalculating what 'line' image to display for what edges differently than was done when the display view was originally generated. Hence an export can look different than what we saw on our monitors.
I actually over-simplified the above explanation. The system also has features like applying 'halo', level of detail, profiles, and edge extensions -- things that all have some aspect of being resolution dependant in how they are applied. It is also noteworthy that even before Sketch Edge technology was added in v6 that there have always been differences between exports and what we see on our monitors whenever the resolutions involved are different.
Now for some advice... (finally)
If you want an image that matches what you see on your monitor the best choice is to do a screen capture. You can use the utilities built into your operating system or stand-alone screen-capture software. Some of you will be saying "but Rossy I need higher resolution!" In that case I'd highly recommend you do your screen capture and then use PhotoZoom Pro2 to effectively improve the resolution of your screenshot. (PhotoZoom is available for macs & pc's and is a very useful graphics tool).
You can also try exporting from SU using the "use view size" option although I've found the results less satisfactory than doing screenshots. In my work designing Styles for distribution by FormFonts I have found that the only predictable output is via screenshots. Some styles will export more faithful to what you saw on your monitor than others - but screenshots always seem to work. Crank up your monitor to its maximum resolution and take your screenshot.In conclusion I'd note to Larry to realize that his use of the '1 pixel' style is in fact using the Sketchy Edge system. If he was using a vector-based edge like is used in SU's "default styles" then he might not have the same export problems.
Regards, Ross
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Thanks for the explanation. That explains a lot.
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Well that clears up alot for me, I was wondering if there was something wrong withe the way i had been exporting images. Thanks for that Ross.
poster-archtech
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