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Subject: 
Re: Bricksmith 1.3: Here's Looking at You, Kid
Newsgroups: 
lugnet.cad.dev.mac
Date: 
Tue, 4 Apr 2006 05:18:02 GMT
Viewed: 
6933 times
  
In lugnet.cad.dev.mac, Allen Smith wrote:
   In lugnet.cad.dev.mac, Travis Cobbs wrote:
   In lugnet.cad.dev.mac, Allen Smith wrote:
   Of course, producing print-quality images using a real-time onscreen design program like Bricksmith just wouldn’t work out well; the images wouldn’t be a high-enough resolution.

The resolution argument actually doesn’t hold up. When I added printing support to LDView in Windows, I made it generate an image using tiling that was at the printer’s resolution (or maybe I maxed out at 300DPI; that was four years ago, so I don’t really remember).

Okay, that puts me in my place. I hereby recant any prior suggestions about crummy resolution! Now that we have established that OpenGL can produce print-quality images, my question is: Can OpenGL produce instruction-quality graphics? Even more germanely, can Bricksmith produce such graphics? I seriously doubt it.

For what it’s worth, I don’t think most people are aware that OpenGL can be used to render images at arbitrary resolutions. Most video cards don’t support rendering directly above 2048x2048. (Presumably the new cards that support 2560x1600 monitor resolution support higher.)

I’d say that OpenGL can be used to make fairly decent instructions. I won’t claim that they can equal the quality of carefully created instructions generated via MegaPOV, but I’d say that they can definitely be pretty good. I uploaded a 5MB PNG file (designed for printing full-page at 600DPI) here:

http://www.halibut.com/~tcobbs/ldraw/private/10030ImperialStarDestroyer1.png

Note that it doesn’t look too great at 100% on your monitor, but it should look pretty good printed. I also scaled the image down to screen resolution, and put the (much smaller) file here:

http://www.halibut.com/~tcobbs/ldraw/private/10030ImperialStarDestroyer2.png


   Usable instructions demand boldly-outlined edges around each part. Bricksmith doesn’t do that, even more so because it doesn’t even draw conditional lines. But even if it did, I don’t think part-outlining would begin to approach what MegaPOV can do, which is to say that it would be well nigh useless.

I’m not sure why. Actually, I think programs that are LDraw-aware can do a better job at outlining, because they can outline exactly what the part authors decided needs to be outlined when the parts were created. The samples above have outlining turned on. By the way, how do you get MegaPOV to draw lines between parts that make up a wall? I thought it’s auto-outlining required changes in depth between adjacent pixels in order to work.

Having said that, conditional lines are going to be slow to draw in an OpenGL-accelerated editor, unless somebody figures out a way to put them into a Vertex program. The above Star Destroyer gets about 12FPS on my computer in LDView with edge lines enabled, but conditional lines disabled. It gets just under 3FPS with conditional lines enabled along with edge lines. It gets 20FPS with no edge lines at all.

In an editor, I think having the edges visible is a huge help to editing, but conditional lines add a relatively minor improvement. Of course, if you’re editing a small file, you can have edge lines and conditional lines, and still get good performance. The Star Destroyer does have over 3000 pieces, remember.


   LPub, meanwhile, is based on POV-Ray/MegaPOV, so it has little bearing on whether OpenGL viewers should have built-in image-exporting

I wasn’t trying to say that it does. I was responding to your point about it not being feasible to automate your work-flow.

   abilities. LPub is essentially a way to automate the highly-labor-intensive render-it-all-by-hand process I use for my own instructions, and can therefore produce output I would deem acceptable. If you want easy and good instructions on the Mac, recreate the LPub workflow! Unfortunately, I don’t have the time to do that; my hands are full enough with an LDraw editor. But it would be fantastic if someone could do it, because I’m the first to admit that my way stinks.

Well, the source is available, but I think it’s in C++ Builder. I don’t know much about C++ Builder, but I’m guessing there’s no easy way to get it up and running outside Windows.

I don’t want to come across the wrong way here. My original comments were made just as a statement that it’s perfectly reasonable to have decent print quality out of an OpenGL app for creation of instructions. I don’t have access to a Mac, so I haven’t been able to look at Bricksmith, but based on the screenshots and the comments here, I think you’ve got yourself a great app. And since your primary goal is to make a good editor, support for these kind of instructions-generation features would just take away from your primary work on the editor. And, to be perfectly honest, producing decent instructions would definitely take a lot of work. I think my comments may have come across as condescending, or implying that you should be taking action based on them. I just want to say here that that wasn’t my intention at all, but reading what I wrote, I can definitely see how it could have been interpreted that way.

Having said all that, if anyone would be interested in STEP support in LDView on the Mac, by all means let me know. I’ve had requests for it on the PC, and it’s on my “to-do” list, but I’ll be honest and admit that LPub’s ability to use LDView as a renderer in Windows really decreased the priority of that feature for me. Not having access to a Mac, I haven’t been the one that has compiled it there lately, but there is a Mac version of the QT LDView. It’s not native, but it should at least work. If I had a Mac, I’d update the Cocoa port of LDView, but I don’t, and it’s not all that likely that I will any time soon.

--Travis



Message has 1 Reply:
  Re: Bricksmith 1.3: Here's Looking at You, Kid
 
Travis, Those images are very impressive! The lines are big and bold, instead of disappearing into the surface they are supposed to be outlining. They are instruction-grade. I will say, however, that MegaPOV does a better job doing stud outlining on (...) (18 years ago, 7-Apr-06, to lugnet.cad.dev.mac, FTX)

Message is in Reply To:
  Re: Bricksmith 1.3: Here's Looking at You, Kid
 
(...) Okay, that puts me in my place. I hereby recant any prior suggestions about crummy resolution! Now that we have established that OpenGL can produce print-quality images, my question is: Can OpenGL produce instruction-quality graphics? Even (...) (18 years ago, 4-Apr-06, to lugnet.cad.dev.mac, FTX)

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