Improve parts with artefacts/ slowly rendering

[Johannes Ahlmann]

Hi,

I am rendering Lego parts using Blender and https://github.com/TobyLobster/ImportLDraw (using "p" "48" ldraw geometries).
Some of the very basic and simple parts take forever to render, and other parts contain artefacts.
Is there a good place to raise a list of parts that are unnecessarily complex or that display render artefacts?

Examples of parts that render extremely slowly (20x slower than complex parts), some of which are the most basic bricks and plates.

2419
2445
2454a
2456
2730
3001
3006
3007
3020
3027
3030
3031
3032
3034
3035
3036
32525
3297
3702
3738
3832
3857
3865
3867
3895
3958
4204
4510
60479
6111
6112
6179
91405
92438

Examples of bricks with artefacts:

• many domed bricks
  
• some bricks that have clearly been assembled from subparts with noticeable gaps/ discontinuities
  

Regards,
Johannes

[Johannes Ahlmann]

Sample images attached.

[Orion Pobursky]

Sample images attached.

This is, most likely, an issue with the converter. We do strive to preventing "gaps" in the interface between rounded and flat primitives but this is sometimes unavoidable. Much thought has been put into this smoothing by other renderers/editors (notably LDView and LDCad), something the converter is probably not attempting.

[Johannes Ahlmann]

OK, thank you for sharing!

I will have a look whether there are other importers that do better smoothing, but since this is coming from the geometry it seems to me that there is a small minority of parts that are causing these kinds of issues, while the vast majority render flawlessly.
I will also try "normal" resolution instead of "high" whether that makes a difference.

Are you aware of somewhere where I can raise these kinds of issues in a structured way, or is this simply not of interest?

I also believe that Mecabrick have high-resolution parts, I wonder if I could use their geometry for the few ones that are causing issues.

Best Regards,
Johannes

[Orion Pobursky]

You might also check out the new export functionality in the LDCad 1.7 alpha that Roland just posted.

[Matthew Morrison]

Hi,

I am rendering Lego parts using Blender and https://github.com/TobyLobster/ImportLDraw (using "p" "48" ldraw geometries).
Some of the very basic and simple parts take forever to render, and other parts contain artefacts.
Is there a good place to raise a list of parts that are unnecessarily complex or that display render artefacts?

Examples of parts that render extremely slowly (20x slower than complex parts), some of which are the most basic bricks and plates.

2419
2445
2454a
2456
2730
3001
3006
3007
3020
3027
3030
3031
3032
3034
3035
3036
32525
3297
3702
3738
3832
3857
3865
3867
3895
3958
4204
4510
60479
6111
6112
6179
91405
92438

Examples of bricks with artefacts:

• many domed bricks
  
• some bricks that have clearly been assembled from subparts with noticeable gaps/ discontinuities
  

Regards,
Johannes

It's possible you have beveling turned on,
which may be the source of your artifact troubles.

As for the performance, if I had to guess, those parts have more than average number of line type 2, which the TobyLobster importer uses to sharpen edges and figure out where to bevel. 

For no other reason than to get feedback, would you be willing to use my importer and compare and post the results?

https://github.com/cuddlyogre/ExportLDraw

It's in active development, so if you like it, please watch the repo so you can be alerted to updates.