iPi Motion Builder BVH Issue

Greenlaw · **Posted:** Sun Jan 16, 2011 4:36 am

I've been teaching myself Motion Builder 2011 these past few weeks, and I'm having problems bringing in the new MB-friendly .bvh data from iPi DMC. If I import an iPi DMC standard .bvh file to Motion Builder, the rig comes in correctly. However, if I try to import an iPi Motion Builder .bvh file, the rig comes in collapsed.

The same issue exists when importing the MB .bvh to bvhacker. Interestingly, the MB .bvh imports just fine to Animeeple.

Obviously I can work with the standard .bvh file when using Motion Builder but I was hoping the MB .bvh export would help streamline things. I was wondering if I'm doing something wrong or if there is a known problem with the iPi DMC MB .bvh.

Thanks in advance for any helpful info.

G.

Greenlaw · **Posted:** Sun Jan 16, 2011 4:43 am

Okay, I see that this is a scale issue. The MB .bvh does import to bvhacker but the scale is very tiny compared to the standard .bvh. I'm guessing the same problem is happening in Motion Builder.

In Animeeple the data is importing at correct scale but maybe that's because Animeeple's defaut scale is based in meters instead of centimeters.

However, I'm a little confused about these results because it's my understanding that .bvh doesn't contain scale data. Could somebody explain why this is happening? Thanks!

Also, is the scale difference between the standard .bvh and the MB .bvh a bug?

G.

Greenlaw · **Posted:** Sun Jan 16, 2011 5:19 am

I was comparing the standard .bvh and MB .bvh files using Notepad++, and I noticed that the Offset values are offset by two decimal places. Could this be what's causing the iPi DMC Motion builder .bvh files to come into Motion Builder 2011 at very tiny scale?

G.

Greenlaw · **Posted:** Mon Jan 17, 2011 2:04 am

I just took another look at the scale issue with the iPi Motion Builder BVH export. When I open the iPi MB .bvh file in bvhacker, the height of the rig is 1.7 (meters I presume,) which sounds about right, but the size does look very tiny in that program (as it does in Motion Builder.) Luckily, it's trivial to scale the rig up or down in bvhacker (Use Ctrl+ + or - to scale the rig by a factor of 2) and resave it. BTW, using scale up (Ctrl+ +) five times in bvhacker seems to produce the correct results for Motion Builder importing. (This gives you a 'mid-thigh' .bvh reference as seen in typical MB tutorials.)

Even though the current iPi Motion Builder BVH scale factor is apparently correct for actual height, I was wondering if it would be a good idea to allow the iPi DMC user to set the scale factor for exporting .bvh to other programs?

G.

Greenlaw · **Posted:** Sat Jan 22, 2011 10:59 am

Here's an illustration of what I'm seeing here. On the left is how a standard iPi .bvh looks in Motion Builder 2011; on the right is the iPi 'MB friendly' version.

G.

Greenlaw · **Posted:** Sat Jan 22, 2011 10:40 pm

Just for completeness, here's a screencap of what I see in MB after I use bvhacker to scale the bvh file up. In this case, I clicked the 'scale up' key (num +) five times (the small yellow skeleton is the iPi MB BVH):

Just to be clear, the actual scale of the .bvh doesn't seem to matter much for the file to function properly in Motion Builder. Being able to import the file at a reasonable scale is more a matter of convenience.

G.

Michael Nikonov · **Joined:** Tue Mar 31, 2009 9:13 pm **Posts:** 805

Thanks for your feedback. You are right. MotionBuilder prefers centimeters as default units. We will change this in next update. We will also implement configurable units for export/import in future versions.

For now, the workaround is to scale up the BVH file using BVHacker.

iPi Motion Builder BVH Issue

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