File Import Formats

Daniel Dapena

Hello everyone,

For my work I usually use Blender for 3D modeling. When we were working with MS Windows and AutoCAD, we used 3ds format as an interchange format.

Well, now we use Ubuntu and Bricscad and we do not have a really useful file format for exchanging drawings between Bricscad and Blender. If the SVG file is large (30 Mb or more) often fails import from Blender.

Is it possible to implement new file import options? Including 3ds format would be great, but at least it should be possible to import COLLADA file format (.dae).

Regards.

Knut Hohenberg

Hi Daniel,

I'm also relying on a combination of Bricscad and Blender for my work - I'm still far from establishing a convenient workflow, but this is how I do it at the moment:

The best solution for me is to export 2d-paths as (r12 or r15) dxf from bcad and import them via the contributed python import script (from Migius) into blender 2.49b. I then do all extrusions (even some booleans) in blender, in order to get clean meshes. I usually stick to 2.49 for modelling because of the large number of useful scripts, and pass on to 2.5x for animation and rendering.

If I have to import 3d-data into blender, I export the model as r12 dxf from bcad, which turns all acis geometry into meshes, and import them using the above mentioned script into blender. In order to see anything imported, you have to check the small "n" in the import dialog to make sure anonymous blocks don't get skipped, since all solids will have been converted to such blocks containing separate polyface meshes for each of the solid's faces. The import script then places these meshes on a separate layer and creates group definitions from them that get inserted on another layer to make up the actual model. Unfortunately, there are some downsides to this:
- the resolution of the meshes cannot be controlled, or at least I didn't find a way to do so (facetres and viewres seem to have no effect)
- each solid produces several meshes, that often will have to be joined and cleaned to give good results in blender
- the resulting structure of the blender file is convoluted and hard to work with (large number of objects, meshes and groups)

My experience is that cleaning up imported 3d-geometry in blender is often more time consuming than remodelling from the imported 2d base geometry. This means that I sometimes model things twice, to get renderings from blender and construction drawings from bcad, which is not very satisfying. Still, I don't think I would be happy with an integrated render in bcad, should Bricsys release this for Linux - it  will almost certainly fall short of the power and choice that blender has to offer. I would rather vote for better 3d import/export facilities - collada seems to be a good way to go.

Lastly, to generate drawings from blender models, I sometimes use the "2d projection" option in the dxf export script, and sketch over the imported geometry in bcad (if numerical precision matters, you should use grid snapping rather than object snapping for this).

Daniel Dapena

Hi Knut,

Although it may sound weird, I'm glad to know there are others with the same problem as me with Blender. I hope they at least take some interest about this matter.

I also redraw from the imported 2d base geometry (and often model things twice, of course) and this can be frustrating. Perhaps in the near future, Bricscad could successfully export dae, 3ds or directly in native .blend format.

Knut Hohenberg

Hi Daniel,

I fear 3ds is a bit too outdated to attract development resources, and blender is too much of a moving target (the binary format was probably never meant to be written by other applications) and not mainstream enough anyway.

Collada, however, would not only ease data exchange with blender, but also open up the door to google sketchup and warehouse, which should make BricsCAD look more attractive to many (at least architects), so this is something we might dare to hope for...

Nuno Gouveia

 Hi,

I'm also tring to establish a decent workflow between Bricscad and Blender. With Blender 2.4x I used to explode/3dconvert the solids in Brics and then export to DXF.

Now with Blender 2.6x I'm unable to do this.

I'll  be downgrading do 2.4x blender I guess.

Do you guys have an news on the subject?

Knut Hohenberg

Not really.
The only change for the better at the moment is the ability to control mesh generation in Bricscad V12. Although I meanwhile switched to blender 2.6x completely, a copy of 2.49b is still indispensable for me as dxf-converter. The ODA is working on a collada-interface (to which Bricsys IMO should have access), so there may be hope for an easier path in the future...

Mikael Nordvall

I would really like to see wavefront .obj file format as an export option from BricsCAD.

Until then... If you are willing to use wine, the Windoze application Accutrans 3D from http://www.micromouse.ca/ can convert various versions of DXF to a number of useful formats. This is a lightweight but very reliable conversion tool and a license only costs about 20 USD. This is what I use until Bricsys can help us with a better and more productive work flow.

Kurt Eichenberger

Nuno and others,

It seems that Blender is putting the option to export to dxf (or dwg) back into Blender.

http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Import-Export/DXF_Exporter

I have not played around with Blender much, but I am looking forward to doing so.

Kurt

Kurt Eichenberger

Blender to dxf

Sorry,

Here is the "hot" link.

Kurt

Keith Frost

anyone use Ayam3D?

i've used it for years and it handles R12 dxf really well.

Nuno Gouveia

Yesterday I've managed to export 3d geometry (solids) from Bricscad to Blender; like this:

1- use 3Dconvert on the solids

2- explode the convert meshes (now you have 3D faces)

3- export in dxf (ascii)

4- Now, in blender (2.65), in the dxf impor window, scrooll down and select iso 8959-15 instead of ascii.

The only problem is that I get a single mesh, without the cad layers separation.

A workaround would be a small coded addon for bricscad to export each layer at a time, a a similar addon for blender to import a bunch of dxf files in one move.... but I'm not a programmer.

Just an idea

Knut Hohenberg

Hello Nuno,

a lisp that exports all layers to separate dxf files wouldn't be hard to write, but IMO it still isn't worth the effort, since you would lose the structure of your model (I'm assuming that a complex model is composed of (nested) blocks).
What we would need instead is an export that translates bricscad's blocks/xrefs into objects with shared meshes or group instances (for nested blocks).

BTW, there is an .obj exporter written in lisp in the making:
http://blenderartists.org/forum/showthread.php?267990-Direct-Autocad-Intellicad-to-Blender-exporter-LISP-to-Download
This one is mainly targeted at getting 2d-geometry into blender, but seems to support meshes as well. The script is said to already run on windows (which I can't verify), but on linux, some needed vlax functionality is still missing (if I interpret the errors right).
I'll post again in this thread when I manage to get it to work...

Keith Frost

in a meeting today the subject of reading and writing 3D PDFs came up.
I honestly had never heard of it before, but i seemed to be the exception.
Any chance of this being supported in the future?

Michael Mayer

I would be interested in a kind of direct exchange from Bricscad to Blender.
Like Vectorworks/Allplan/Archicad to Cinema4D or ACAD to 3DSMax.
(Would love to have that from Bricscad to Modo too)

Importing Geometry is not such a problem.
I use the DXF AddOns in Blender and export older DXF, to avoid ACIS Solids.
Or better, I go Bricscad >DWG > Vectorworks > FBX/DAE/... > Blender

But like Vectorworks to C4D/FBX/DAE/ .... I would like a lossless import
Objects/Layer/Hierarchy/Material/Cameras/Lights/....
from all Info I feed Bricscad with.

I think since the latest Blender developments over the last years you can't
avoid looking at Blender. 2.79 is great. But for me 2.8 at the end of the year
will have an even larger impact.

Tom Foster

This is still a bit mystery-land to me, but the advent of Point Cloud, along with similar work by photogrammetry, brings such crossover/interworking into vital importance. Brics is presently rushing to catch up in this with Adesk, Bentley etc, but great, mould-breaking developments are expected soon.

While presently still struggling to learn to get fast and accurate photogrammetry results for everyday buildings incl their occupied interiors, I'm v aware that the next step will be to import/export basically mesh output freely with vector-based CAD. And i'm hoping that Point Cloud enablement in Brics will arrive just in time.

So it's not just about Blender - that's just one of the tools in the stack.

Mikael Nordvall

Since collada (.dae) export and import was introduced in BricsCAD this is our choice of file format for exchange of data with blender. Recent versions of Blender support collada without the need to install any 3rd party plugins.
We also use the command line interface of Blender to turn Blender into a conversion tool, in order to convert BricsCAD collada exports into the preferred output format (in our case wavefront OBJ).

Michael Mayer

Yes, but DAE export from Bricscad is the most basic kind of "save as"
option I have ever seen.
I lately tried again and I will not touch that as long I have other DAE
export from CAD's that brings me Hierarchies, Names, Materials,
Instances, .... in a nearly lossless form instead.