LDraw Pattern Creator/ LDPattern Help

[Daniel Goerner]

Hi,

I'm totally new to anything CAD (well, except LDraw and MLCad, but only moving bricks from A to B). I'm building some Star Wars models, but there are so many printed parts missing. I was trying to recreate the pattern for 30116pb03 (Panel 14 x 14 x 2 2/3 Quarter Saucer Top with Millennium Falcon Pattern) (yes, I know, maybe hard stuff for a beginner, but that's the part I really want) and came across all the programs like LPC and LDP. The principle is clear. Import a part, draw a lot of triangles, save, done. But there are the things between these points, that I don't get. At least not by tial and error. For example: I'll import the part 30116.dat. Fine. And now? How do I get one of the 15 facets to the right position? How do I position the background image right? When I zoom in the part, all I see is the middle. So, how do I scroll left/right or up/down? Since I'm stuck here and did not even get to the "draw a lot of triangles" point, I turned to the Sticker Generator, which was a suitable alternative (for me). I made stickers for every single facet of the part (and after 3 days work, not every sticker 100% accurate, be it in size or position), the final part and subparts being about 12 MB (!), which made the pov file quite heavy. Anyway, I really like to do it right, so anyone who has some experience with LPC or LDP could you please at least tell me, how do I get to the "draw a lot on triangles" part?

Thank you.

[Tim Gould]

Hi Daniel,

If you're only interested in having the stickers on the povray model you can texture map an image file onto the right surface. I can't give you an example right now as my internet access and time is limited at the moment.

But perhaps someone else can?

If you want them in LDraw as well it's much, much harder. But doing it POV only is a thought.

Tim

[Daniel Goerner]

If someone has the knoledge how to do this it would be nice if he'd share it. But I'd still prefer the "real" way.

[Jean-Philippe Ouellet]

If you happen to read french, see this excellent documentation by J.C. Tchang.

Nils Schmidt once said he was working on an english translation, but I'm not sure if it was ever completed. I think I remember some more recent talk about translating it (or maybe it was another document) but for some reason I can't find it right now.

As for what Tim was suggesting, see this, but it wont help much unless your only end goal is to make nice renderings of the model.

[Daniel Goerner]

Dammit, I should have read that guide by J.C. more carefully (although google translator converts it to something like "guess what the author means"). Some of the points I mentioned are described in there. Let's see how far I can get with this...

[EDIT] I've just seen, that J.C. updated the guide today....

[Daniel Goerner]

I'm working on a Torso Pattern. A noob question: How much triangles are too much? I'm half way through the pattern and have almost 500 triangles. And should I use quadrangles for bigger areas (or where they fit)? As I said, I've never done this before so any help is appreciated.

[Christian Neumann]

A noob question: How much triangles are too much? I'm half way through the pattern and have almost 500 triangles.

Daniel,
tha's not a noob question, but it depends on the pattern. There are simple patterns with less triangles/quads (like 973p09), and complex patterns with a lot more, e.g file 973pq1 is a double sided torso with 488 triangles and 2069 quads (which make whole of 4626 triangles).

What you can do is to design the bigger details (= clearly visible at normal zoom level) with more triangles/quads than smaller ones, to smooth curves for example. But that is also a point of taste, because if you do a pattern of 5000 lines, you wouldn't care about saving 20 or 50 lines, eh? Just find your best way between details and filesize, if you make a bigger one, you can "optimize" and downsize it later. If you computed your pattern (means import from bmp or bmp2dat), the size is usually very huge. That is another reason (exept from having fun ;-) ) for doing it by hand.

[Daniel Goerner]

Thanks Chris. I'll try it and see what happens. But how do I make quads in LPC? I find options for triangles and primitives, but no quads...

[Christian Neumann]

As far as i know, you can't create them directly. LPC uses Philo's Rectifier tool to merge adjacent triangles to quads under some circumstances, when exporting to .dat. Personally i don't like that, because i have no control of this "optimization". It works fine on flat patterns (e.g. torso, flag), but if you project the result onto a formed surface, these quads possibly are broken back to triangles. For me that's a reason to use LDPattern, although it has only very basic functionality and some bugs...

[Philippe Hurbain]

It works fine on flat patterns (e.g. torso, flag), but if you project the result onto a formed surface, these quads possibly are broken back to triangles.

I agree with you, it maybe quite annoying. I met this problem while doing this pattern. I solved the issue by changing colors of a few triangle pairs that I wanted to be assembled together. That's a trick useful to control behaviour even in "normal" use, for example to keep symmetry in the middle of a shape issued from LDD.

[Daniel Goerner]

I already thought that it would depend on colors which triangles would be converted to quads.

Oh, and Philo, while you are here, how do I flatten a surface in MLCad? You wrote that in your guide for "projector". If I'll ever leave conception phase for my torso pattern (I'm drawing it in Photoshop with all the triangles so I already know where to put the vertexes in LPC, because PS is a program I know really well unlike LPC), and finish it, I'd like to try my luck on 30366px4. How do I start there. Copy the 30366.dat to a different folder and delete the subfiles, so I have just the surface left? That was the first thing that came to my mind. But maybe I'm all wrong...

BTW: Thanks to everyone who posted so far.

[Philippe Hurbain]

Oh, and Philo, while you are here, how do I flatten a surface in MLCad?

Basically you select everything that needs to be flattened and (to flatten in y direction) set all three y transformation matrix coefficient at 0.

(screenshot from this tutorial that can give some more insights...)

You wrote that in your guide for "projector".

Note that Projector is somewhat "deprecated", Slicerpro is the tool to use...

If I'll ever leave conception phase for my torso pattern (I'm drawing it in Photoshop with all the triangles so I already know where to put the vertexes in LPC, because PS is a program I know really well unlike LPC),

Phew :p Good luck! IMHO if you are able to master Photoshop, you should find LPC rather easy to use

How do I start there. Copy the 30366.dat to a different folder and delete the subfiles, so I have just the surface left? That was the first thing that came to my mind. But maybe I'm all wrong...

Indeed, that's essentially what you need to do.
Then import the .dat file in LPC (you may need to inline everything using LDDP first). Use proper projection direction and "import projection data", this will create a template on which you draw the pattern. In this mode, LPC is even able to do the projection, but not to slice pattern at facet boundaries. But I am myself discovering this section of LPC, so I can't give much more tips...

[Daniel Goerner]

Thank you. Maybe when I'm done with my first torso, you'll be able to give more info. ;-)

[Daniel Goerner]

Wow. I'm officially excited.
After 4 days of preparation in Photoshop it took only a few hours to finish the part. The handling of LPC is easier than I thought. The finished part looks awesome. And 60 KB compared to over 1 MB when I made the pattern in Sticker Generator is also not bad. So, what do you think?

There's one question left so far: How can I select a single triangle in the middle of a lot of other triangles to change the color or delete it?

[Philippe Hurbain]

Wow. I'm officially excited.
After 4 days of preparation in Photoshop it took only a few hours to finish the part. The handling of LPC is easier than I thought. The finished part looks awesome.

Yes, LPC is a great tool that I use more and more with pleasure.

And 60 KB compared to over 1 MB when I made the pattern in Sticker Generator is also not bad. So, what do you think?

I have not analysed it closely, but it does look great!

There's one question left so far: How can I select a single triangle in the middle of a lot of other triangles to change the color or delete it?

You have 3 modes depending on the objects you will be working on: vertices, triangles and primitives (shortcut F2..F4). When you are in triangle mode, and neither in add vertex/add triangle modes, just click on a triangle to select it (its border turns red). You may then change its color or delete it (Del key).

[Philippe Hurbain]

Had a closer look... Definitely good, except that there are two triangle overlaps, outlined in red in the attached file. This file was obtained using Edger2 as described here, bottom of page.
BTW, what torso is this?

[Daniel Goerner]

Thank you. Corrected it.

That's Qui-Gon Jinn from 1999.

[Philippe Hurbain]

Perfect! Parts Tracker is waiting for it...

[Daniel Goerner]

Is it possible in LPC to attach a vertex to a border of the part? By now I'm working with CSG intersection points, but maybe there is an easier way. It tried with moving a vertex that has a triangle attached and sometimes it worked and sometimes it attaches to the wrong border. I don't get how this works.

[Philippe Hurbain]

By now I'm working with CSG intersection points, but maybe there is an easier way.

That's what I do (eg. on this part)

It tried with moving a vertex that has a triangle attached and sometimes it worked and sometimes it attaches to the wrong border. I don't get how this works.

I was not aware of this method - too bad it's not consistent!

[Daniel Goerner]

Is it right, that when I mirror something in LPC, only the vertexes are copied, not the triangles? Because in JC's manual it looks like the triangles are also copied.

[Daniel Goerner]

I found it out myself. Just too much triangles. Switched to performance mode and then it worked.