wiki:FAQ

Version 1 (modified by leo, 10 years ago) (diff)

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General Questions

  1. The array command doesn't do anything, what's going on?

You must set the total number of bricks in the array to a value greater than 1.

  1. How can I set the default options for a new project?

Go to the preferences dialog, set the options you want and press the 'Make Default' button. LeoCAD will save those options and use them next time you start a new project.

  1. I can't seem to align two bricks correctly, they are always away from each other.

Most of the times when this happens it's because the bricks are not where you think they are, they are actually far away and because of the perspective distortion you think they are near each other. Take a look at the picture and compare the Top and Side views with the Main view.

  1. How can I export a model to use with LDraw ?

Just choose the "Save As" option from the "File" menu and enter a file name with the .dat or .ldr extension.

  1. Do you plan to port the program to another platform ?

Not at the moment, I would like to write a Machintosh version but I don't have a Mac. If you're a programmer and you want to try to do it yourself, join the developers mailing list.

Windows Questions

  1. The print/print preview freezes my computer and the HD goes crazy.

The computer is not frozen, as Windows 95 can't print an OpenGL image directly, LeoCAD creates a bitmap in memory and then prints that bitmap. If you are using a high resolution printer, that operation will take a lot of RAM memory. Here's an example, suppose that you want to print something with a 600 DPI printer on a sheet of paper A4, the bitmap would be 8.27 inches x 600 DPI x 11.69 inches x 600 DPI x 3 bytes (24 bits) = 100 MB just for the bitmap. You should go to the preferences dialog and check the box 'Low quality' under the 'Print' tab, that will make LeoCAD use 75% less memory but the quality will be a little worse.

  1. LeoCAD used to work fine but now it crashes on startup and I can't live without it!

Try running "regedit.exe" and delete the folder "HKEY_CURRENT_USER\Software\BT Software" and it will work again.

  1. I try to run the program but I get a crash on startup.

Most regular PC video cards are tested mainly with games and LeoCAD uses the hardware more like a CAD program so a lot of times it ends up finding bugs on their drivers. The first thing to try is go to your manufacturers website and download and install the latest drivers available for your video card.

If that doesn't work you can go to your Windows desktop, right click on the "My Computer" icon and select "Properties" from the menu. A dialog will appear, click on the "Advanced" tab and move the "Hardware Acceleration" slider all the way to the left. If this fixes your crash then the bug is in your video card drivers.

ATI cards are a good example of bad OpenGL drivers, if you get a crash and the message says "LEOCAD caused an invalid page fault in module ATIO9XAA.DLL" then you have bad drivers. You can try what's listed above or simply rename the ATIO9XAA.DLL file on your windows/system directory.

Linux Questions

  1. Where can I find libGL.so?

If you don't have any OpenGL libraries installed you can use Mesa 3D, make sure that you add the directory where you installed it to your /etc/ld.so.conf file and run ldconfig or have it in your LD_LIBRARY_PATH environment variable.

  1. What does "_mesa_unpack_ubyte_color_span: Assertion `dstComponents > 0' failed." mean?

This is a problem caused by old versions of the Mesa 3D library (the version that comes with RedHat? 6.2 for example). Go to the Mesa Homepage, download and install a newer version.

  1. The program crashes every time I try to save a picture.

This is a bug in the nVidia X11 drivers, I've contacted them but they haven't fixed it yet. If you have Mesa 3D installed you can run LeoCAD with "leocad --libgl /path/to/libMesaGL.so" to save pictures.