to test I made a simple box in C4D with dimensions of 1,0.5,1 Cinema units then exported as FBX. when I imported FBX file into Houdini, it is 225, 112, 225 units. so question I have is there a model size Houdini won't work with?

for instance. I make a building in C4D with size of 100, 50, 100 Cinema units, importing FBX into Houdini (if it follows above scale) then it would be 22,500 by 22,500 Houdini units. suppose it was 1,000 by 1,000 Cinema units, so, in short, would there be a point where Houdini would get bogged down by shear size of an imported object?

I don't think so. We're talking about cm and meters here right? I think size is just an arbitrary number to Houdini, remember we're primarily talking about point coordinates. I can see having to raise the far distance of the camera frustum if necessary.

what is your cinema project scale unit set to?

if you make sure it's in meters your conversion to houdini should be 1-1, or if you have a way to specify units on export to fbx

generally in CG you want to avoid too big and too small numbers due to rounding errors they may produce

One of your main problems is viewport control. The OpenGl view appears to be 32bit, ~7 significant figures, so it quantizers quite badly any values from about 10,000 upwards, progressively getting worse, as you can see in the attached gif where the box is at 3,000,000. Interestingly Mantra appears to work fine.

I can confirm that objects exported from C4D and then imported in Houdini Indie get seriously scaled upwards. A 200 cm default cube/box in C4D will be many meters tall in Houdini. I'm not sure if it is a Cinema 4D or Houdini error.

Island
I'm not sure if it is a Cinema 4D or Houdini error.

I don't think it's an error, it's a unit conversion thing. C4D uses cm and Houdini uses meters as the base unit. So your 200cm model comes into Houdini as a 200 meter object. I pretty much make it a routine to add a transform node with a uniform scale of .01 to just about any geometry that I bring into Houdini.

Houdini Units are meters.

most (all?) other apps - C4D, Maya, Max - the default is cm

so if you are in C4D and your units are set to cm and you make a box that is 100cm square
then bring this into Houdini it will be 100 meters square.

ALWAYS check your working units if you are moving anything from one app to another.

then be consistent in how you deal with scale.

I'd recommend scaling on Export (scale in the app you made the thing) - so in C4D, scale the object down by 100, then export to Houdini. You could make this a little workflow script thing.

There does seem to be some issue with Houdini. In C4D, one can specify the unit size of a cube in cm, meters, etc. Regardless, the fbx export from that is imported in Houdini in the wrong scale. Ditto Modo. I can specify the size of a cube in Modo as 1x1x1 meters and when it is exported as a fbx and imported in Houdini, it will be the wrong size. It is true one can transform the objects prior to export in the host program or after import in Houdini; but I would think that when units are specified, this should not be necessary.

but I would think that when units are specified, this should not be necessary.

Houdini uses ‘Units’ - units have no size just a number - Houdini by default sees that number in meters.
so if you make something that is 325mm in C4D and import it into Houdini it becomes 325m ->
(325mm == 325 Units == 325m in Houdini by default)

goldfarb
Houdini Units are meters.

most (all?) other apps - C4D, Maya, Max - the default is cm

so if you are in C4D and your units are set to cm and you make a box that is 100cm square
then bring this into Houdini it will be 100 meters square.

ALWAYS check your working units if you are moving anything from one app to another.

then be consistent in how you deal with scale.

I'd recommend scaling on Export (scale in the app you made the thing) - so in C4D, scale the object down by 100, then export to Houdini. You could make this a little workflow script thing.

thank you for the reply. I will change default to mm and see what that does.

bobc4d
I will change default to mm and see what that does.

Don't do that, it will make it even worse. Rather change the default to meters instead of centimeters.

yeah I was backwards thinking