Models and Renders

 From:  Michael Gibson
946.4 In reply to 946.3 
Hi Ed, I am glad it worked to fix up that one model to work how you wanted.

> The key word in your program description is "sharp edges". I ran the program
> on a model with curved surfaces and radiused corners and it did not break apart.

To be more precise, it goes through the OBJ file and makes a separate object for every "smoothing group" that it finds.

When MoI exports an OBJ file, there will be one smoothing group defined for each connected chunk of polygons that share the same vertex normals.

Polygons along a sharp edge get different normals, so they create boundaries between different chunks of polygons, separating things into different smoothing groups.

There is also another way you can create smoothing group boundaries - by turning off welding.

When you save to an OBJ file, the "Meshing options" dialog will pop up that has the slider on it that you can use to adjust the density of the generated polygon mesh. In the bottom-left corner of that dialog is a little double down-arrow, if you push it the dialog will expand with more options.

One of those additional options is "Weld vertices along edges" - by default this is turned on, but if you turn it off then the mesh that is generated for each surface of your original solid will have separate points instead of sharing common points along edges. This will also have the effect of further dividing smoothing group information so that each separate surface (whether it has sharp corners on its edges or not) will be in a different smoothing group.

So if you turn off welding it should help you break down smooth objects as well.

The only difficulty is that some programs may create a visible crease in between unwelded areas that are supposed to be smoothly shaded, if they try to calculate shading information manually instead of using the shading information directly from the OBJ file...

> Is there any possibility in the future for the user to select an area directly,
> or perhaps define the threshold, for object division?

Yes, there will definitely be some work on this for version 2.0 - I'd like to make it possible to assign different basic materials at least to different faces and then export those material assignments to the OBJ file. Hopefully Bryce will read that data from the OBJ.

- Michael