Export 2 part prop

pwiecek

I would like to export a 2 part prop from a model. For example, a control that has a base ansd a knob that turns. Following the directiond in various other posts, I can get the base and the knob but but I cant get the centers lined up so the knob will rotate correctly. I would also like to position them so that they rotation on X Y Z axes made sense and have theeir default position at the origin. I am not particularly skilled with Blender or other 3D program.

My current workaround is to keep them together and parent them tp an invisible sphere.

Any suggestions?

NorthOf45

You can adjust the center position of the knob with the Joint Editor Tool. Yes, okay, there are no joints on a simple knob, but every object has a center point. Parent the knob to the panel where you want it to be. The panel's Center Point might not be at zero, and if you save it that way, it might load off in the distance. Select the panel and move it to the center of the world coordinates, then select the Joint Editor Tool, and go to Tool Settings. In the viewport you will  see two small xyz axis systems, one green (Center), one red (End). Adjust the Center and End Point values or drag the axes to the center of the panel.

Now select the knob, and do the same sort of thing with the Center point to get it at the center of rotation you want. As you turn the knob, the Center Point won't change, but the End Point will move with the rotations. You can move the End point somewhere close just to keep it in the picture, but it doesn't change anything at this level.

If you want to get fancy, hide the translation/rotation/scale controls that are not required and rename the one you use to something representative of the knob's function. You can also set limits on the knob's rotation if you don't want it to spin more than a certain amount, say from -120 to +120. Use the Parameter Settings on the sliders (the gear icon in the upper right corner) to make the changes.

I don't think those changes will get saved with a Scene Subset, but try that to see if it does. Add the saved Scene Subset back in (don't delete the original, or you'll lose the changes if it doesn't work). If it did save the changes, you should be done. If not, to make the changes permanent, you'll have to Save As... -> Support Asset -> Figure/Prop Asset(s) or Save As... -> Support Assets -> Save Modified Assets if you had previously saved them as Figure/Prop Assets. This step is necessary because you are defining new props. You might have to do that for both parts since they are not joined in any way, like a figure with bones and rigging. You can then save the two pieces parented together as a scene subset for later use.

You can see this sort of arrangement on some products where every piece is a separate prop, each parented to something else. The alternative is to create a figure by exporting the two parts as an obj, then reimporting and setting up face groups, then adding bones and rigging with weight maps, a much more complicated process.

pwiecek

Thanks, Ive tried that but I cant determine the exact center or position the pivot point accurately enough. Is there a way to reduce the sensitivity of the sliders?

NorthOf45

The sliders for Center and End Points in the Joint Editor Tool are not that sensitive, in my opinion. You can also drag the axes with the mouse pointer, or type in values manually (click on the numbers to get an editable field). Is the object very small, perhaps? You could scale it up, adjust the Center Point, then scale it back to original size.

pwiecek

Yes, they're small. Normally I don't have this problem, but the fact that one of them is rotating against the other makes any misalignment VERY obvious.