My first (non-patterned) parts!

[Mikkel Bech Jensen]

Hello everyone! I have been using LDraw many years now and I have managed to contribute to the library with some patterned parts in the past. Now I'm back and I have made my first 'real' parts (which isn't just a pattern on an existing part) using the LD Part Editor. However I'm shure that there are a few problems with parts so I am making this thread in the hope that it can provide additional help for these parts to be accepted and for my future improvement as a parts author

Here is the parts:
http://www.ldraw.org/cgi-bin/ptdetail.cg...30585a.dat
http://www.ldraw.org/cgi-bin/ptdetail.cg...30585b.dat

[Willy Tschager]

Hello everyone! I have been using LDraw many years now and I have managed to contribute to the library with some patterned parts in the past. Now I'm back and I have made my first 'real' parts (which isn't just a pattern on an existing part) using the LD Part Editor. However I'm shure that there are a few problems with parts so I am making this thread in the hope that it can provide additional help for these parts to be accepted and for my future improvement as a parts author

Here is the parts:
http://www.ldraw.org/cgi-bin/ptdetail.cg...30585a.dat
http://www.ldraw.org/cgi-bin/ptdetail.cg...30585b.dat

Impressive work and congratulation to your first part!

I wouldn't have modelled the top of 30585s01.dat:

1 16 0 32 -24 32 0 0 0 0 -32 0 34 0 48\2-4cyli.dat

First because it is hidden by the rest of the structure, second 'cos it doubles the polycount in combination with:

1 16 0 32 -24 0 0 32 -32 0 0 0 -6 0 48\1-8cyli.dat
1 16 0 32 -24 0 0 -32 -32 0 0 0 -6 0 48\1-8cyli.dat

I use prims only if they save me time and effort.

w.

[Mikkel Bech Jensen]

That's true. I changed the top so there won't be any hidden faces on the final piece. What do you mean about the prims? Is it ok to not use primitives even if it would be possible to scale a primitive to fit a certain place? It's very difficult to scale and rotate some primitives to fit excactly the intended place.

[Magnus Forsberg]

Hello and welcome. Very impressive work.
To me, finding the most suitable primitive is a big part of the fun in making parts.
Creating subfiles is also good to do. Make small files and reuse them, mirrored or rotated.

In this case, five subfiles might be to many. A left/right half + short/long tubes, would be a better solution.
Since this is a transparent part any internal surface should be avoided , if possible.
Edge-lines inside a transparent part becomes very visible.


  30585b.png (Size: 397.56 KB / Downloads: 111)

[Willy Tschager]

What do you mean about the prims? Is it ok to not use primitives even if it would be possible to scale a primitive to fit a certain place? It's very difficult to scale and rotate some primitives to fit excactly the intended place.

I'd say the scale of using prims or not is yourself. I use prims when they safe me time and effort and stop fitting them in when I get annoyed. This is a hobby and should be fun, but as you read Magnus' comment the definition of fun might be something totally different.

w.

[Mikkel Bech Jensen]

I really had the impression that it was prefered to have primitives everywhere possible. I somehow assumed that it optimized the LDraw files for the various LDraw programs each files were into subfiles and primitives (I'm absolutely not an expert on this subject ).

I have combined some of the subfiles here and requested a deletion for the now unused subfiles. However I have not changed the geometry so there wouldn't be any internal surfaces for the '30585b' part. That would be a lot of work and I feel that I would become insane if I work much more on these right now I will propably take it up at another time

[Philippe Hurbain]

I had a quick look at your parts, and they are very good ;) The thing that bothers me (related with internal surfaces) is "bleeding ", surfaces that end in the middle of other surfaces (tube ends in the middle of part sides). This is visible even with opaque parts.

Otherwise, my rule of thumb for primitive usage:
- whenever possible, use special primitives for studs, anti studs, bars, clips etc. Not only they simplify part design, they also often provide connectivity automatically, or at least will help defining it.
- it is generally valuable to use primitives for all round elements (cones, cylinders, discs and rings). They improve part look, especially when seen with primitive substitution with high number of segments (using ldview). Getting a good look with substitution can be very tricky though, bad designs can result in gaps or overhangs!
- I use other primitives such as boxes or triangular prisms only when they simplify design. Benefit of using them is pretty low otherwise... Used to be good to reduce file size, but in this era of multi GB hard disk this becomes a moot point  !

[Mikkel Bech Jensen]

Please disregard my earlier comment. I think I have fixed the problem with internal surfaces on '30585b'. Though I remained the top surfaces under the studs. I assume it's ok in this case? Besides that I have removed and replaced most of the primitives and rearranged the surrounding quads and triangles. Now there is a significant reduction in overall polygons (obviously). I don't even know why chose to have that many primitives in the first place 

[Mikkel Bech Jensen]

Please disregard my earlier comment. I think I have fixed the problem with internal surfaces on '30585b'. Though I remained the top surfaces under the studs. I assume it's ok in this case? Besides that I have removed and replaced most of the primitives and rearranged the surrounding quads and triangles. Now there is a significant reduction in overall polygons (obviously). I don't even know why chose to have that many primitives in the first place 

Also I completely missed some duplicated quads. Mostly because LDPE didn't warn me about them. I was told about a reviewer on the parts tracker and I don't how that was spottet in the first place? Is there that can spot that better than LDPE. I don't LDDP found them either. However I don't remember excactly and I can't double check that anymore.

They are of course removed now.

[Magnus Forsberg]

Also I completely missed some duplicated quads.

Odd.

All three error checking programs I use, found the exact same duplicated quads in the old s\30585s01-file.
LDPE, LDDP and DATHeader.

DATHeader is The tool to use for error checking, and autocorrection, before uploading.
In your parts, it also tells us that the description is incorrect. There must be double spacing in the size dimensions.

~Hose Joiner 2 x 4 x 3 - Tube Joiner A
~Hose Joiner  2 x  4 x  3 - Tube Joiner A

Do you see the difference?

[Nils Schmidt]

Also I completely missed some duplicated quads. Mostly because LDPE didn't warn me about them.

I will implement a detector for overlapping planar surfaces in the future.
You can also use the random colour render mode to spot flickering areas.
These are normally a good visual indicator for overlapping or duplicated surfaces.

You did a nice job on your first 'real' parts!

[Mikkel Bech Jensen]

I think these parts are pretty much done now. Is anybody up for confirming if they really are?

I have optimized the geometry so there should not be any unnecessary vertices
I have remade both so there is no any internal surfaces
I have closed some gaps and fixed some T-junction issues

Unificator could not merge some of the vertices to the primitive's vertices. The only fix I could come up with was to delete the primitives and replace them with quads, so now there are even fewer primitives in parts. I guess there would have been too many decimals for the vertices coordinates for unificator to allow merging with primitives.