problems exporting the obj file Tweet

[andrear]

hi tigs,
I have a problem when i try to export only the obj to update the ocs previously setted.
when it is loaded by the ocs the materials, even if not changed at all in the skp file, are coming out partly messed up.
in particular some of the materials are beig trasformed in the skp default mat.

thank's in advance for your answer,
andrea

[TIG]

Without the SKP or OBJ etc I have to guess but I suspect that you have modeled some faces 'backwards'.
View your SKP in Monochrome mode, with a Style having a distinctive color for the default back-face material [typically 'bright-blue'].
Wherever you see the back-face material Octane will render that visible surface as 'default' [usually 'buff'] even if in the SKP it has a material.
Although a SKP with some faces that are the wrong way round can look OK in Sketchup most 3rd party renderers will render faces as they have been told - i.e. back-faces are not to be seen so they are in the 'default' color...
All is not lost - if you read the Help PDF there's a section about using some of the utility scripts supplied in the zip file with the main exporter - i.e. FixReversedFaceMaterials - Select the problem faces in the SKP and run that tool to flip the faces to face the right way and also transfer the material that was wrongly used on the back correctly onto the front - keeping UV-mapping etc - which can be a pain to fix otherwise as it'd need redoing if the face is 'reversed' manually...
As you model remember to use Monochrome mode regularly to check the correctness of your faces' orientation.
Also remember that all objects need a thickness - so no single skin window panes - otherwise one side will not render as hoped...

[andrear]

thank'you tig,
those procedures surely help in general cases, but what if the same obj is exported from the same skp using the 'render image' button, keeping intacts all the materials?
Can it be that using the 'export obj only' button the exporter read the mats differently?

andrea

[TIG]

No.
When you export OBJ/MTL it makes those files.
When you 'Render Frame' it makes those files and then opens the OCS using them, to make the rendered image.
If the OCS is using a different named OBJ that was previously imported [manually or by this tool] compared to the OBJ you've just made [i.e. without the +render option] then the OCS will open later one and use the initial OBJ, not the new one you've made as it's not the same file and not linked to the OCS...
Why do you want to export the OBJ/MTL without rendering ?
If you render as well that OBJ is linked to the OCS...

[andrear]

ok Tig,
understand it.

thank's,
andrea