Hey guys,

How would you approach such an animation with complex CAD geometry: https://micromat.de/wp-content/uploads/2019/02/Schwenkspanner.mp4 [micromat.de]

I tried to cut the object in half with the standard boolean node and a box as “cutting” geometry, but I'm getting weird edges, weird normals and everything is slow.

In general, does anyone know how such CAD-cut-in-half animations are made? With Houdini, Maya, C4d? Or with standard CAD software?

Thank you very much!

The clip node is usually faster than the boolean for cutting, but you'll need to cap the geometry yourself. Capping is as simple as removing unshared edges(divide SOP) if the geometry is closed (watertight).

Boolean may be required for more complex cutter shapes. To ensure the normals are good, make sure the geometry already has good vertex normals before cutting.

To avoid weird normals with boolean, both the original geometry and the cutting geometry needs vertex normals. It seems like in this video he is not cutting it live, but have separated the geometry first and then render one of them with opacity. Some renders like Vray and Arnold can do this in rendertime.

jsmack
The clip node is usually faster than the boolean for cutting, but you'll need to cap the geometry yourself. Capping is as simple as removing unshared edges(divide SOP) if the geometry is closed (watertight).

Boolean may be required for more complex cutter shapes. To ensure the normals are good, make sure the geometry already has good vertex normals before cutting.

I tried the clip node, and it worked better. But with this node, I cannot animate the cut, so that it moves into the geometry.

How would you make sure, that the vertex normals are good? Facet node?

ThomasRunning
To avoid weird normals with boolean, both the original geometry and the cutting geometry needs vertex normals. It seems like in this video he is not cutting it live, but have separated the geometry first and then render one of them with opacity. Some renders like Vray and Arnold can do this in rendertime.

I guess you are right, with the seperation bevorehand. But how did he make this smooth opening cut, which reveals the inner parts?
Could it be an exported animation from a CAD software?

it could also be render time booleans which some renderers support and I guess it would be preferable especially for heavier geo

PhiiLL

ThomasRunning
To avoid weird normals with boolean, both the original geometry and the cutting geometry needs vertex normals. It seems like in this video he is not cutting it live, but have separated the geometry first and then render one of them with opacity. Some renders like Vray and Arnold can do this in rendertime.

I guess you are right, with the seperation bevorehand. But how did he make this smooth opening cut, which reveals the inner parts?
Could it be an exported animation from a CAD software?

If you look closely its not a cut, its two pieces thats split in two, and then he rotates the front piece inside the other. You can cut it live, but he didnt.

tamte
it could also be render time booleans which some renderers support and I guess it would be preferable especially for heavier geo

Alright, thank you

ThomasRunning

PhiiLL

ThomasRunning
To avoid weird normals with boolean, both the original geometry and the cutting geometry needs vertex normals. It seems like in this video he is not cutting it live, but have separated the geometry first and then render one of them with opacity. Some renders like Vray and Arnold can do this in rendertime.

I guess you are right, with the seperation bevorehand. But how did he make this smooth opening cut, which reveals the inner parts?
Could it be an exported animation from a CAD software?

If you look closely its not a cut, its two pieces thats split in two, and then he rotates the front piece inside the other. You can cut it live, but he didnt.

Thank you!