terragen Vector map output through mudbox to maya

[kmac]

sorry for the duplicate post - but maybe someone can help.

so - say my maya cam exported fbx is at a scale of 100 - keep the geo back and forth at a scale of 1.

if my simple shape is set to a 5000 untit square..

displace a 1x1 plane in mudbox with this 4k vector map - displace with absolute tangent - leave the advanced values at default
limit the displacement value to 5

export said displaced plane back into maya..

try and get that to line up with the exported obj from the terragen file.. scale of ?
16.6 seems to generate the 5000 unit square, but that is off from the terragen exported geo -
17.5 seems to get close..

but there has to be actual accurate values for this.


my original simple shape is 5000 units, with the displacement value left at 2000

my mudbox knowledge is limited -

right now i know my values are off in this chain, as the displaced geo from mudbox and the exported geo from terragen are not matching... even with what feels like an appropriate scale on the mudbox geo.. the displacement height and the exported terragen geo do not line up.

any help appreciated. It would be so great to be able to get cleaner export geo back into maya with this method for holdouts etc.

thanks!

krista

[Matt]

Hi Krista,

I can't think of any reason why 16.5 or 17.5 would work. I would try to simplify the process first by taking the sculpting/displacement out of the equation, and see if you can just work with planes and get Terragen and Mudbox to both export a plane of the same size.

I assume you're exporting the OBJ from Terragen with the Micro Exporter, is that right? When you export the 5000x5000 area from Terragen, how big is it in Maya? Have you got cameras to match up correctly with the Terragen terrain in Maya (before bring Mudbox into the equation)?

If you export a 1x1 plane from Mudbox to Maya, how big is that in Maya? If it's not 1x1 (or some multiply of 10), can you find someone with Maya and Mudbox experience to help you figure out why?

Matt

[digitalguru]

Hi Krista,

Attached my script for Maya which should help you out with your scale issues. I wrote it to make sure scale was consistent through Terragen and Maya. It can import an obj output from the MicroExporter from Terragen and export a camera (albeit a custom camera generated by the script) back to Terragen via a chan file which works pretty well. There is an FBX camera export as well (though not tested as well as the chan for any bugs).

I think your problem with the mudbox displacement is that it should match the Terragen terrain. So if your terragen terrain is 8000 x 8000 units (meters) then you should create (or export from Maya) a plane with those dimensions.

if my simple shape is set to a 5000 untit square..

In your case then I think the plane would need to be 5000 x 5000 unit, but I'd have to check that.

leave the advanced values at default limit the displacement value to 5

If you have the working units setup correctly in Maya, you shouldn't have to change the displacement value (as you said to 5) at all - it's a multiplier, so the highest point of your terrain is 1500m (for example) then the maximum value of your vector displacement map (in the green channel) should also be 1500.

It might be an idea to add a function to my script that exports a basic plane that could be exported to Mudbox for this purpose.

any help appreciated. It would be so great to be able to get cleaner export geo back into maya with this method for holdouts etc.

Absolutely - outputting the Terragen terrain as a vector displacement map makes for a very accurate method for generating holdouts etc - do you have a good renderer for Maya? (Vray, Arnold?) - you could import the VDM and displace a plane directly inside Maya, which would save you making a hi-rez displaced plane from Mudbox - though that would work as well)

Have a go with the script, any problems, drop me a line and I'll talk you through it.

Graham