Reverse engineering sw

[davide445]

Ok so received the scanner we are testing it.
First work before the propeller one is a pair of eye wear.
Understood before thinking about RE we need to have a clean mesh to work with.
I can use DAVID 4 and other free sw to create and clean the mesh, but I still need to remodel where the scan is not complete on tiny or internal parts such as the hollows or guides.
I did read good things about 3d-coat, any other suggestion?

[awerby]

You don't need a perfect mesh to do RE; you just need enough of it to reconstruct important features. So, for instance, if you had a cylindrical boss on your original part, all you'd need was three good points on the mesh to recreate the circle, and one on top to show you where to end the extrusion. The mesh is just for reference, and once you've created the CAD model you can dump it - the CAD model is your final product.

3DCoat is intended for modeling organic objects, texturing them with UV maps, and remeshing them to clean up your models, but I don't think it makes any claims for being a reverse-engineering tool, or something that will perform mesh repair on scans.

Andrew Werby
www.computersculpture.com

[davide445]

You don't need a perfect mesh to do RE; you just need enough of it to reconstruct important features. So, for instance, if you had a cylindrical boss on your original part, all you'd need was three good points on the mesh to recreate the circle, and one on top to show you where to end the extrusion. The mesh is just for reference, and once you've created the CAD model you can dump it - the CAD model is your final product.

3DCoat is intended for modeling organic objects, texturing them with UV maps, and remeshing them to clean up your models, but I don't think it makes any claims for being a reverse-engineering tool, or something that will perform mesh repair on scans.

Andrew Werby
www.computersculpture.com

Difficult to understand the complete workflow.
In that perspective you suggest we need to use a CAD and remodel from scratch the object, using the mesh just as reference to ease the work.
I suppose this is just fine for mechanical parts with easy geometry, made from a mixture of solid primitives.
But with more complex objects such as eyewear or the propeller will be not better to have the full mesh, using specialized tools such as VRMesh Reverse, 3dreshaper Meteor and SpaceClaim to first reconstruct the complete mesh and next model a complete solid using semiautomatic generation tools that will use the complex mesh as guide?

[JSenior]

Difficult to understand the complete workflow.
In that perspective you suggest we need to use a CAD and remodel from scratch the object, using the mesh just as reference to ease the work.
I suppose this is just fine for mechanical parts with easy geometry, made from a mixture of solid primitives.
But with more complex objects such as eyewear or the propeller will be not better to have the full mesh, using specialized tools such as VRMesh Reverse, 3dreshaper Meteor and SpaceClaim to first reconstruct the complete mesh and next model a complete solid using semiautomatic generation tools that will use the complex mesh as guide?

Have you got an image of the eyewear you can share?
For most reverse engineering applications (depending the reason for RE and the data format they require) you're using the mesh as your template/guide and cleaning the mesh serves little to no point. It will only make the data less accurate.

[davide445]

Have you got an image of the eyewear you can share?
For most reverse engineering applications (depending the reason for RE and the data format they require) you're using the mesh as your template/guide and cleaning the mesh serves little to no point. It will only make the data less accurate.

Attached the first test scan, only of the frontal part without the temples

[JSenior]

Attached the first test scan, only of the frontal part without the temples

For the basic shape you're going to want to create a surface over the front face and then draw around the profile of the glasses, project this on your surface and delete the excess. Once you have the basic curved shape the extrude it by x mm (assuming it is consistent) and can add some rads to the edges. If the lenses are recessed you can make a cutter using a section of what you've already created.

You can do this in Spaceclaim/Rhino/Most other solid modellers (It can be done in Designspark but creating the front face is difficult as there are no blend/surfacing tools.) There's no point trying in a mesh program however, as you won't get consistent sharp edges. Depending how clean your mesh is, you may want to smooth the front face to be able to create a smoother surface.

This will all take you time to learn however. When I purchased my first scanner (and I was using CAD before this) I spent 6 months doing no paid work before I was comfortable taking on clients projects.

[davide445]

For the basic shape you're going to want to create a surface over the front face and then draw around the profile of the glasses, project this on your surface and delete the excess. Once you have the basic curved shape the extrude it by x mm (assuming it is consistent) and can add some rads to the edges. If the lenses are recessed you can make a cutter using a section of what you've already created.

You can do this in Spaceclaim/Rhino/Most other solid modellers (It can be done in Designspark but creating the front face is difficult as there are no blend/surfacing tools.) There's no point trying in a mesh program however, as you won't get consistent sharp edges. Depending how clean your mesh is, you may want to smooth the front face to be able to create a smoother surface.

This will all take you time to learn however. When I purchased my first scanner (and I was using CAD before this) I spent 6 months doing no paid work before I was comfortable taking on clients projects.

Useful suggestions, thanks. Using SpaceClaim we will have RE tools available, using "clean" Rhino without any RE addon such as RhinoResurf or Mesh2Surface will be difficult? Trying to understand the most cost/effective investment for our learning, considering we are just starting.
We will probably proceed step by step, starting with just the scan and mesh preparation, and giving to colleagues the difficult reverse part and next learning how to.
A second project is a shark tooth (attached the first scan), a definitely more organic shape. We need later to print it in 3d: we will need also to pass trough a CAD and solid modelling or we can stay with the mesh and just give them a depth and make it watertight?

[JSenior]

Assuming they want a like for like model then no reason to put into CAD. Scan, mesh, fill the holes, smooth out any problems, align it to the world axis and then maybe cut a plane off the bottom and fill so it will sit flat.

[davide445]

Assuming they want a like for like model then no reason to put into CAD. Scan, mesh, fill the holes, smooth out any problems, align it to the world axis and then maybe cut a plane off the bottom and fill so it will sit flat.

In this case any suggestion for a good tool?
I think I did now understand the CAD topic, about mesh there are many more options, I did have on my laptop for testing Meshmixer, Netfabb Private, 3d-Coat, Meshlab, VRMesh Reverse, GOM Inspect, Cinema 4D, will need a lot of time just testing every of them.

[awerby]

It looks like the first step is to resolve the two scans you got of that shark tooth into one. Have you been able to do that with the software supplied with your David scanner? I agree - you don't need reverse engineering to get from a STL file like that (once you've unified and cleaned it up to produce a water-tight mesh) to print.

Andrew Werby
www.computersculpture.com