Rendering LDRAW Reloaded & MECABRICKS

[Michael Klein]

Hello,

it's a while ago I posted on the forums. In 2014 I made an intense research how to get LDRAW geometry into SOFTIMAGE and later MODO. What looks easy due to several export formats like OBJ or 3DS it's not that easy to get proper and error free meshes. Well, I worked out a not simple workflow and got some promising results what made me sticking with it.

Not to mention that LEGO is the mother of all 3d and the best and most amazing toy on this planet. :-)

Due to the time consuming process to import bigger models I was looking for alternatives and found MECABRICKS. At this stage this amazing webiste of a one-man-army called Nicolas Jarraud was just made for building your models, save them online and show them. I got in touch with Nicolas 'SCRUBS' Jarraud because this great alternative to LDD and other editors was screaming for a render feature. I sent him a list of ideas for features like exporting in a format what supports instances to make bigger models easy to handle and that he should find a way to add LEGO logos onto all studs.

What should I say? This nice person implemented everything in record time and it was blast. While my former LDRAW Millennium Falcon UCE model took two days to export - import to BLENDER - export - import - cleanup - get ready to render ... the same model built in MECRBRICKS took finally 15 minutes ready to render when I had my material scene completey setup.

The fact that MECABRICKS is a gift with a huge potential - far more intuitive to use than LDD in my opinion - I passed all my research results at this time to SCRUBS to help him to create a nice BLENDER setup what you can download on the MECABRICKS forums with a tutorial. SCRUBS was inspired and added more ideas by himself. I helped him with the German translation and new people with talent showed up on the forums rendering nice pictures even without any 3d skills.

MECABRICKS is growing slowly because adding new parts need model skills and an understanding for perfectionism to follow the guidelines how to model parts correctly for MECABRICKS. A few months ago I told SCRUBS that a LDD-importer would be awesome. Well ... added ... still beta but works like a charm.

Yesterday I went back to LDRAW. I finished my material setup based on the actual state of my MECABRICKS development and did another test.

Feel free to take a look at my Artstation portfolio

[Merlijn Wissink]

Those are some very, very nice renders. I love 'm.

I'm wondering: what makes it that the Mecabricks parts-system is better for rendering (exporting) than LDraw? Or isn't it really the parts-system, but more the exporting tool that's just 'better' than LDraw based tools?

There was a lot of discussion a little while ago about updating the LDraw specification/system or even making a complete new LDraw parts-system. As usual (don't get me wrong everyone, I'm not angry, that's just a feeling I get from that discussion everytime ) the discussion died and nothing ever came out of it (as far as I know). But what would make LDraw (in your opinion) better for the 'modern' 3d modelling world?

[Damien Roux]

I guess the library itself is the problem. The geometry is low quality and it is very hard to obtain realistic rendering when everything is edgy and sharp. Today using thousands of facets in a mesh in not a big deal anymore. I guess that's why ldraw format looks a bit outdated.

Many people have found tweaks to get better rendering using native ldraw format, but I must say that to get to the next level, higher qualit parts are needed. Look at LGEO: it doesn't use any of ldraw geometry, all the available parts have been recreated.

Good thing would be to keep actual ldraw for building and have a ldraw 2.0 library to render.

[Willy Tschager]

There was a lot of discussion a little while ago about updating the LDraw specification/system or even making a complete new LDraw parts-system. As usual (don't get me wrong everyone, I'm not angry, that's just a feeling I get from that discussion everytime ) the discussion died and nothing ever came out of it (as far as I know). But what would make LDraw (in your opinion) better for the 'modern' 3d modelling world?

You will surely remember that this has been discussed before:

http://forums.ldraw.org/showthread.php?t...8#pid15668

w.

[Michael Klein]

The difference is that MECABRICKS has an export feature supporting so called "instances" of master bricks. One master as a real model. 1.000 instance copies just for rendering. This will keep the scene of even bigger models extremely small with good performance.

The editor is very easy to use and intuitive. Once you have built the model you export it in a second and import it in a second. Extremely easy. Of course the model meshes are a bit lower but overall good for renderings. I wished they were in a kind of subdivision/nurbs format to keep it resolution independend. I had a discussion with the maker of MECABRICKS. He never thought about rendering and to rebuild everything is too much work for one person. He definitely needs support.

For the parts you don't need bevel edges. I use a rounded edge shader implemented in MODO what Nicolas Jarraud (MECABRICKS) adapted for BLENDER. This is a good solution with good results keeping the geometry simple. But it's not 100% correct because the studs have a bigger bevel. I can live with that.

I also recognized that LDRAW models are not 100% measured correctly. You will see that when comparing the studs with real LEGO and MECABRICKS models. As I understand this is a result of the LDRAW format.

All available export methods from LDRAW-tools (3DS, OBJ) failed. Then I found the BLENDER add-on and this worked but it's extremely slow when importing bigger models.

Example:
The Millennium Falcon UCE model will take via BLENDER many hours to import to BLENDER. Importing to MODO with clean-ups till ready to render will take again a few hours. Let's say you have to invest two days.

With MECABRICKS the same model will take a few seconds to export and a few seconds to import. In around 10 minutes the scene is ready to render.

The LDRAW screne takes around 1GB. The MECABRICKS scene around 40MB. Because of instances.

And another important difference: MECABRICKS is using hi-res textures for the decorations while all textures are modeled in LDRAW. This will also cause bad shading artefacts especially at Minifig-Faces/Heads.

I love LDRAW because of its huge library. But MECABRICKS is actually the way to go.

[Gerald Lasser]

The difference is that MECABRICKS has an export feature supporting so called "instances" of master bricks. One master as a real model. 1.000 instance copies just for rendering. This will keep the scene of even bigger models extremely small with good performance.

So if I understand you right, it is mainly the available programs to export a LDR scene that make life hard when handling LDraw models. As the LDraw suite also handles basically instances of the bricks it should not be magic to get something fulfilling this requirement.
The exporter shall then include all geometry of the bricks used in a model (as instances) and also the position of those instances.

The current exporter gives you only a huge mesh, right?

[Michael Klein]

The current LDR-Importer gives me a scene with separate bricks. Every bricks is merged with its studs and in my case the LEGO logos because I modifed LDRAW for that.

It's great to have each brick merged because this is important for some things like modifying models in my 3d software like I could do in MLCad, LeoCAD etc. for animation, hiding objects or other operations.

LDRAW would of course offer to create instances by the modular system. That means you could also do instances of the LEGO logo and the studs what would shrink the scene data extremely but then I will run into a problem when I use the important "rounded edge" shader. This shader will simulate small beveled edges to make the bricks looking more complex and real.

An exporter has to export each brick as a separate merged object with material. For a software like MODO the instances have to be grouped by geormetry and color.

If there's a option for maximum instancing then each model is a group of elements with their instances. Beside the issue with the rounded edges shader it could be that huge hierachies of models with instances are not really good for the scene performance. You might lose the benefit of instances in this case. When you have a model like the Millennium Falcon with over 5200 bricks it's better to have the instance master merged bricks + instances = 5200 bricks instead of 5200 model groups with single studs incl. instances of those studs. No. It's better to use merged meshes of each brick with studs and LEGO logos.

Optionally you should have an option to turn LEGO logos on or off for export.

What's also very important. Before I import my fbx-model from BLENDER I load a scene with the complete LDRAW material setup in MODO. I will delete the materials which were imported with the fbx-model and they will be replaced by my final materials. My scene is just made for the fbx-results. Another exporter would create different color tags. For MECABRICKS I use a different material scene because the COLLADA-result looks different to BLENDER.

[Gerald Lasser]

Just on the TV (ARD) in a quiz show two kids and Carrie Fisher guessing LEGO Star Wars model assembling in a nice animation from a heap of parts.

I instantly thought that needs to be your work, did you generate these animations?

[Michael Horvath]

Is there a way to import LDR into Mecabricks? Is Mecabricks powerful enough to handle all of Datsville?


https://www.eurobricks.com/forum/index.p...w-project/

[Philippe Hurbain]

Is there a way to import LDR into Mecabricks? Is Mecabricks powerful enough to handle all of Datsville?
https://www.eurobricks.com/forum/index.p...w-project/

AFAIK there is no LDraw import (but you'd better ask Scrubs on Eurobricks!). One (convoluted and lossy) way is to convert Ldraw to LDD and import LDD to Mecabricks. At least it would allow you to check performance level.