LDD data to DAT

[Orion Pobursky]

I seem to recall a tutorial that was written (by Philo?) on how to process the LDD mesh data into a part for the PT. My Google fu has failed me in finding it. Can someone point me in the right direction?

[Philippe Hurbain]

I seem to recall a tutorial that was written (by Philo?) on how to process the LDD mesh data into a part for the PT. My Google fu has failed me in finding it. Can someone point me in the right direction?

Here is my Lugnet post (was the opportunity to revisit this old friendly place ) https://news.lugnet.com/cad/?n=17697 refering to the initial post on Eurobricks.
But all LDD part meshes not yet converted to LDraw should be available on digital-bricks.de . And if you need a part that IS on PT (eg. to check geometry), just ask me!

[Orion Pobursky]

Here is my Lugnet post (was the opportunity to revisit this old friendly place ) https://news.lugnet.com/cad/?n=17697 refering to the initial post on Eurobricks.
But all LDD part meshes not yet converted to LDraw should be available on digital-bricks.de . And if you need a part that IS on PT (eg. to check geometry), just ask me!

So you answered the question I asked. Thanks for the effort. But I didn't ask the right question.

The question I really wanted to ask was if there was a procedure/tutorial on step to take to clean up the converted file for the PT.

[Magnus Forsberg]

... if there was a procedure/tutorial on step to take to clean up the converted file for the PT.

Here is a summary of how I do it. I use LDPE for all of this.

1.
Reposition the mesh so that the origin will be according to ldraw standard.
2.
Study the part and look for symmetries, or repeting design features. "How do i subfile this?"
3.
At the same time study the part and think "What primitives can I use?"
Stud primitives?  Box primitives?  Stud-group primitives?  Pinhole primitives?

Replacing a primitive.
4.
Start by selecting a few triangles, and then use "Select/..connected../..and stop selecting at edges"
or   "Select/..connected../..with same type".   Give all you selected a colour.
Place the primitive you want to use in a correct position. And remove all your coloured ldd mesh.
5.
Use Ctrl+E to snap a ldd-vertex to a primitive vertex.
Select a vertex you want to move. Hold down Ctrl and select a target vertex in the primitive. Press E.
Use "Alt+V" to create an extra vertex between two selected vertices.

Creating subfiles
6.
Use Sym-splitter to divide the mesh into "sub-files". Don't cut surfaces in the cutting plane. Sym-splitter will arrange the mesh into three groups. Select the half you want to keep in the text editor, and create a subfile from your selection.
7.
Delete the other half of the ldd mesh, mirror or rotate the subfiles, and keep also all triangles and primitives that happened to be in the cutting plane, in the main file.

Now it's time to think of patterns.
8.
Select all the triangles you think will be covered by the pattern. Give them a colour. Select "All with same colour" and "Join the selection" by right clicking in the 3D-viewer. Give it a name in a comment "0 // any text ...." so that you remember what file it should go to, and sort the coloured sections.
9.
Is the surface smooth enough, or maybe concave/convex? Select two adjoining triangles and press "F" to flip them.
10.
Are all the edge lines you want present, or to many? Add or remove edge lines.
11.
Generate conditional lines using Edger2.
12.
Move all coloured surfaces to a another sub-file/files, or back to the main part. (You might need to create a mirrored section, in the mainfile.)
a.
If the entire new subfile will be coloured by giving it a colour code in the main file, it should contain all of the cond-lines covering that surface. You don't want to have blue condlines on a yellow pattern subfile e.g.
b.
On the other hand, It is often a good idea to have all condlines in the same, main subfile. That way you don't have to copy all the needed condlines into every patterned part, or subfile you make.

Finishing
13.
Use DatHeader to clean up your files and to give them a correctly formated header. It is also very good at optimizing your code into quads, thus reducing the filesize. It can even create rect primitives, if you set it up to do so.

Note that I didn't use Rectifier (in LDPE or DatHeader) until the end of the clean-up. I want to have as many triangles as long as possible.
Please, also note that creating a new vertex after you have used Edger2 to make condlines, will often result in a set of corrupt condlines.
Delete all condlines and generate a set of new lines, if you have manipulated the mesh after using Edger2.

[Orion Pobursky]

Awesome thanks Magnus. In addition to wanting to do some of these myself, a good workflow tutorial will encourage others as well. I'll probably post what you wrote to the wiki (at some point).