Stainless Steel Braid

lukasz_piziak

Hi,

Does anyone know how with Onshape Stainless steel Braid can be acheved? With Render Studio I can not find anything what may look as a braid.

On attached image braid was modeled (AutoCad) and rendered (3dsMax). Any ideas?

Paul_Arden

If the braid is not modelled in Onshape (which would of course been a lot of quite heavy geometry) then the only real option in Render Studio would be to apply it using textures. Unlike 3ds max we don't have an option to convert curves to geometry with thickness (at least not yet). While there are some meshes and other appearances in Render Studio none of them would quite look like the image you showed.

To get closer you would need to make your own braid textures to match what you want to have. You would need at least two textures, one for a bump or normal map and another for a cutout map to make the holes. I've knocked up a couple which are similar to what you showed in the image which are attached. You can upload those to Onshape and use them with a custom appearance. With those I can get something like this:

Of course without actual geometry it is always a compromise since the silhouette edges of the object won't be affected by the bump map and you don't get self-shadowing and so on. Also there is no actual thickness to the braid so you can't really cut into it and show the cross section as you do in the image you showed (that would of course only be possible with real geometry).

Note that lighting environment will affect the look quite a bit since how noticable the bump map is will depend a lot on the reflections and which direction the light is coming from so experimenting with this can help.

Here are the steps I used to create what is shown in the image above. It is based on a horizontal cylindrical shape like that shown in the example picture. The projector method would need to change if the alignment is different or if using arbitrary shapes. Of course my textures are just examples, if you want something specific you'd have to create the texture by hand. I used Illustrator and Photoshop for this with basic gradients but other tools could of course work. For the bump map lighter regions are treated as higher and darker as lower. In any case here are my steps for my example.

1. Right click in a blank area of the scene graph, select "Create UV projector…"
2. In the dialog that appears give it a recognisable name and hit "Create"
3. Select the newly created projector in the scene graph
4. View the selection properties in the right panel and change the "y" value in "Rotation" to -90 and all three components of the "Scale" to 0.01
5. Click the caret next to the projector in the scene graph to expand it and then select the item under it
6. In the properties click the link for the "Projector function" property to edit the projector
7. Change "projection_type" to "projection cylindrical and ensure "coordinate_system" is set to "texture_coordinate_object"
8. Search the appearance library for "flex", select "Flexible material model" and assign it to the braid
9. Search the appearance library for "cutout", select the "Add cut-outs" and assign to the braid (this combines those two appearances)
10. Ensure the braid is selected and the "Appearance" tab on the right is active
11. Search the appearance library for "bitmap", select "Bitmap texture" and drag it on to the "Cutout" property of the appearance
12. In the "Bitmap file" property click the "Actions" button and choose "Select…"
13. Pick the "braid_mask.png" image (or if you don't have it imported yet click "Import…" at the bottom of the dialog
14. Ensure the "Scalar mode" is set to "mono_average"
15. Set the "Rotation" to 45.0
16. Click the "add_cutout" link at the top of the tab to go back to the top level appearance
17. Click the link for the "Base material" property to go to the main appearance
18. Search the appearance library for "bitmap", select "Bitmap texture, bump" and drag it on to the "Bumps" property in the "Global" group (you may need to expand that group)
19. In the "Bitmap file" property click the "Actions" button and choose "Select…"
20. Pick the "braid_bump.png" image
21. Change the "Bump strength" to 2.0
22. Set the "Rotation" to 45.0
23. Click the "flex_material_v2" link at the top of the tab to go back to the main appearance
24. Search the appearance library for "bitmap", select "Bitmap texture" and drag it on to the "Base color" property of the appearance
25. In the "Bitmap file" property click the "Actions" button and choose "Select…"
26. Pick the "braid_bump.png" image
27. Set the "Rotation" to 45.0
28. Set the "Contrast" to 0.7
29. Click the "flex_material_v2" link at the top of the tab to go back to the main appearance
30. Set the "Metallic material" to 0.8
31. Set the "Reflection roughness" to 0.2

If you want to adjust the tiling of the texture you can select the projector you made in the scene graph and change the "Scale" under the "Transform" section. Smaller numbers will make the texture repeat more often and larger numbers less often. In my example I re-used the bump texture for the base colour, however you may get better results with a different or adjusted texture that has less contrast.

Obviously "how to make a braid in 31 easy steps" is a bit more complexity than we'd like to see for this but right at the moment if you need something specific rather than generic there are quite a few extra steps needed. We certainly hope things like this can be made easier in the future.

lukasz_piziak

Hi Paul,

Thank you very much for these 31 easy steps. I will definitely try this method and share my results with you. I agree that it may not give a 3D feeling like the real geometry, especially where you can see a cross-section.

I was able to import curves into Onshape and create a 3D model of each braid wire. Unfortunately, the document is quite heavy, and any attempts to make further modifications like adding new parts or cutting the braid end have resulted in no success.

I hope that Onshape will eventually provide an option to render curves with a thickness, similar to what is possible in 3DsMax.