kicad-developers team mailing list archive

[Mário Luzeiro <mrluzeiro@xxxxx>]

It is forced to compare STEP and WRML.
Also, the WRML result could be better or worse (to the eyes) than the STEP rendering.

When render engine is rendering a STEP, it will first pre process it and internally convert it in a format to be rendered. The result will depend on internal conversion method, conversion properties and the color information from STEP.

When render engine is rendering a WRML file, it will read the triangle information and materials (as from Cirilo explanation) from that file. There are no guesses or additional triangle added. This is a different format with no equivalent relation between the two formats.
If the exporter of the WRML will make a very bad process and conversion to triangles, so the result will be worse.

Also (as addition to Cirilo explanation), when you convert a STEP to a WRML file you will add material (render material properties) information by yourself. That information was not stored and is not possible to store on STEP files.

> I exported the textured
> model from FreeCAD in both STEP and WRML formats. When I use the textured
> models in pcbnew I find the WRML models look better than STEP

Another clarification,
3D viewer does not support any kind of 3D file formats and textures (face triangle texturing).
So "exported the textured model from FreeCAD" does not sound right to me. You may mean export with colors or with materials (on WRML).

When you choose the option on 3D Viewer to use "textures" while rendering on raytracing (don't remember the name of the option) it is using a procedural generated textures assigned using some logic based on materials. (it will "guess" the texture to use by the material type assigned on the model)


If you still didn't check, please have a look on the StepUp tool for FreeCad from Maurice. It is helpful to convert STEP to WRML and assign materials.

Mario Luzeiro

On Tue, May 9, 2017 at 3:19 PM, Kevin Cozens <kevin@xxxxxxxxx> wrote:
> I've noticed that you can get better material appearance in the 3D viewer of
> pcbnew if you use WRML models vs STEP models.
>
> I created a model in Rhino 3D and saved the model in STEP format. I imported
> the STEP file in to FreeCAD and textured the model. I exported the textured
> model from FreeCAD in both STEP and WRML formats. When I use the textured
> models in pcbnew I find the WRML models look better than STEP. The STEP
> models look a bit flat. The WRML version of the same model with the same
> texturing looks a little more realistic vs the STEP based model.
>
> I don't know why there should be a difference in how the 3D viewer of pcbnew
> renders the two versions of the same model.
>

That's easy - STEP has a simplistic RGB model while VRML has a much better
material appearance model. The two models are worlds apart; STEP for example
has no transparency, reflection, and ambient lighting but VRML does. This is why
MCAD colors look so awful no matter what you do and every MCAD has a
proprietary scheme for managing material appearance for the renderer.

- Cirilo