custom GDL object export to C4D?

[Anonymous]

Hello,

When I make a custom window on the floor plane out of walls and slabs and then save it as a window everything seems to work well. However When i export my model to cinema 4D using archicad exchange the materials of the custom window parts are turned into GDL materials. This is fine and they can be changed to suite or new materials applied to the gdl object. However when i make changes to the archicad model and re-import into C4D then all information is lost and it doesn't recognise the existing GDL materials - sometimes giving the objects new names (numbers). Has anyone found a way to solve this?

Cheers,
Rob

[owen]

Are you exporting objects from ArchiCAD grouped according to Material or Class? Using the ArchiCAD Exchange plugin i've only ever done this by Material.

And are you importing the updates via C4D's Merge, selecting the updated .AC4D file and selecting the appropriate Cinema object group tagged with the ArchiCAD Tag?

Sorry if these questions seem obvious .. just making sure.

Using this process Cinema should remember what material was mapped to what ArchiCAD material, however the names of the ArchiCAD materials need to be exactly the same between updates - this is how Cinema knows what is what. Any changes to a material name, or a new material applied to an object will break the mapping to that object in C4D .. perhaps this is the problem? If you are re-saving/recreating the GDL object in ArchiCAD then could it be generating new materials each time? Try to stear clear of any GDL-named materials .. uses ones from your normal materials list - you know they haven't changed.

If not then i'm at a bit of a loss .. i have never seen this happen, i've found the Exchange plugin to be extremely reliable.

[Anonymous]

Thanks for your reply Owen. And yes to all of the above with regards to exporting by material and merging files. The building form updates fine and so too do the materials in every object except the custom windows or doors that I have made and also 3D party cars that we have in our office library - im not sure where they came from originally as they were here before me but they are part of the archicad transport library. Basicall any object that comes through with a GDL material won't update as it thinks its is a new object - even though it was there in a previous export - so it brings in a new material with the same name which means if you don't delete it you will get mulitple copys of the same original material.

I can't speak for the cars but I make all my windows and doors (using walls etc on the floor plan) using standard materials so that isn't the problem. A work around with the cars is to place them and export them initially then take them out of the archicad group in cinema - then don't export them again. But you can't do that with windows.

I think the problem lies in the exporter might be reading the material settings in the object parameters rather than in the GDL script as custom windows don't automatically have any parameters (you have to do that your self) and the cars materials are all set to 'general' by default even though they are the correct colours in the 3D window - hence exporting their own GDL materials.

My point is - why does archicad exchange not pick up on the fact that it has the same material name which starts with GDL and then a few numbers?

I wonder if graphisoft know of this bug - im assuming its a bug? Should i write to them or maxon? Could the translator read from the GDL 3D script rather than the parameter settings for all objects that are listed as general for their material or don't have any parameters?

Cheers,
Rob

[owen]

OK did some quick tests and i think i've worked out what the problem is..

when you modify your objects and resave them, are you selecting 'Editable GDL Script' or 'Non-editable Binary 3D Data' ? .. the latter is the default unfortunately and should be changed (See attached image)

I tested both methods - the first references materials from your files Material list in the script. I modified (resaved) a test object several times and when updating in Cinema the material names stayed the same, maintaining the mapped Cinema materials.

However using the binary method, although the materials i had assigned to elements in ArchiCAD did not change, each time i resaved the GDL object it creates a new material name internally - in the form of the ArchiCAD materials name prepended with GDLMx_. With a binary object you can't see this in the GDL editor, but when i merged the file into Cinema a new material was created. e.g:

Original - GDLM6_Concrete
1st Update - GDLM9_Concrete
2nd Update - GDLM12_Concrete

and so forth

With binary objects the material mapping in Cinema was maintained with updates as long as i had not resaved (overwritten) the GDL object in ArchiCAD. If i had the above occured.

I think understand why the GDLMx_ is prepended - the materials are defined internally to the object so they can be moved from file to file and not rely on that material existing in that file. Each time you resave it is essentially rewritting the script and it has no clue what name it used in the last save (as you are just overwriting it) - this is why it changes each time.

So the fault here is not Maxons - the material name change occurs within ArchiCAD when you actually create the object, not when you export it to C4D.

hope this helps

[Anonymous]

oh thanks owen for your time. Yes i had noticed that sometimes things were coming through ok sometimes - i think i changed the setting to create a wallhole for my custom window which would only work with one of the options - i forget which and that seemed to remember the original material. I think i will try resaving all my car models to see if that helps. Yes i didn't think it was maxons fault they are usually pretty good when it comes to reliable products. Now if maxonform could be extended to use materials and use the new c4d 10.5 dwg import then that would be something - unlikely though if graphisoft have anything to do with it!