Need explanation of Flexsim drawing commands

Does anybody have a good summarization of Flexsim drawing commands? It seems there are different types of drawing commands. Some are using view as a parameter, e.g. the drawtext command. Some do not have veiw as a parameter, e.g. the drawcube command. Sometimes the drawing commands are embed in opengl commands glBegin and glEnd. Sometimes they are not. I am confused. I just started to learn opengl, mainly for custom draws in Flexsim. Since there is little information in Flexsim help on custom draws, it would be very helpful if someone can give me some hints here. Thanks for the help!

I'm sorry to hear this is confusing. I spent a fair amount of time before the v4.3 release organizing and providing better documentation for all the drawing commands including the new flexscript available OpenGL commands. I deprecated all the older duplicate commands that I thought were causing confusion as well.

Actually in reading your post, it sounds like you have a pretty good handle on what the issues are. Just about any of the commands that draw something that do not start with gl___ are going to be embedded inside of a glBegin and glEnd behind the scenes. Of course those commands that allow you to specify a color and/or texture for the shape it draws are most definitely going to require this.

If you want to write the most efficient draw code that you get to have the ultimate control of, then use all OpenGL commands. We're lucky we get to use them in flexscript now. It makes it easier to experiment and see the effects of our code immediately in the view window!

It's not hard to learn OpenGL, all you really need to know is that it works on the concept of "states". In other words, the OpenGL draw environment is always in a given draw state (or mode) that you can manipulate with commands, and then every draw type command written afterwards is going to draw based on the current state. There are commands to change the color state, the coordinate system, the lighting, etc..

Next, just read through the Flexsim command documentation for all the gl__ type commands and you will get a good idea of how it works because several of the commands have nice examples associated with them. I included the most information regarding drawing in OpenGL space in the command documentation of the glVertex3d command (incidentally, the 3d at the end of the word refers to 3 double precision values and not 3 dimensions - you might also come across an f which stands for floating point precision value).

I've also attached a short Power Point Presentation that AJ Bobo prepared a long time ago for a FlexSimposium conference session where he taught the basics of OpenGL. You might find it helpful, just keep in mind things might have changed slightly since then.

Hi Cliff,

I did not mean your work is not good. Actually, I find that I was looking at the old 4.1 (maybe 4.30) document yesterday when I was in my home. And I was wondering why gl command is in under the math group. And this morning when I am in the office having the 4.32. I see the difference in the help document. It is much better and having examples. I will update the Flexsim version on my home computer. Perhaps the best way to learn is to play with those commands in Flexsim through examples.

Thanks for the attached OpenGL slides. I appreciate your help.