Page 1 of 1

Stones scene

Posted: Wed Jul 03, 2019 4:10 pm
by asm3d
Hello everyone! Here's a scene with a recent scan I made. Once I got an optimized model (8k tris/4k quads), I put it in SketchUp and then I used MSPhysics to distribute all the copies.

stone_SP1_1w.jpg
Final pic (Thea for SketchUp v2 · Presto · 512 s/p · 10 min)

stone_SP1_2w.jpg
SketchUp pic (textured solid style)

stone_SP1_3w.jpg
SketchUp pic (quads and profiles)


You can check the scan here:
https://sketchfab.com/models/5cde4862c1 ... f508a382cf

Re: Stones scene

Posted: Wed Jul 03, 2019 8:10 pm
by DavePSB
Very cool. Can you tell us a bit about your scanning setup? Is this a model built by photogrammetry software based on a number of still photos? Or is this some sort of laser scanner? What hardware/software are you using?

I have been using Meshroom with great success. Good results with a relatively low number of photos (25-50).

Oh, and how did you remesh the scan? Looks very clean and good quads.

Great work.
Cheers.

Re: Stones scene

Posted: Thu Jul 04, 2019 7:37 am
by asm3d
DavePSB wrote:
Wed Jul 03, 2019 8:10 pm
Very cool. Can you tell us a bit about your scanning setup? Is this a model built by photogrammetry software based on a number of still photos? Or is this some sort of laser scanner? What hardware/software are you using?

I have been using Meshroom with great success. Good results with a relatively low number of photos (25-50).

Oh, and how did you remesh the scan? Looks very clean and good quads.
Hi Dave! For this scan I used Agisoft Metashape Standart Edition, it's not free but its price is quite reasonable (179$). I used 97 photos to get a raw 3d model with 1,4 million faces or so.

Once the raw model was made, I took it to Instant Meshes, a open source retopology tool. The retopology destroys the UV mapping so I went to Blender to: 1) Create a new UV's for the quad model and 2) bake the texture and normals from the raw model to the quad model.

I've heard good things about meshroom so I have to give it a try, for sure.

Re: Stones scene

Posted: Thu Jul 04, 2019 9:09 am
by JQL
I also use metashape standard but didn't know about instant meshes. Seems great and I will try it. Thanks for the heads up

Re: Stones scene

Posted: Thu Jul 04, 2019 9:37 am
by asm3d
JQL wrote:
Thu Jul 04, 2019 9:09 am
I also use metashape standard but didn't know about instant meshes. Seems great and I will try it. Thanks for the heads up
I'm planning to release a tutorial about this in september (I'm currently moving to a new house and I also want to do a holyday trip to Manchester so I'm quite busy these weeks). Anyway, let me know if you get stuck with instant meshes or baking the textures.

Re: Stones scene

Posted: Thu Jul 04, 2019 11:58 am
by JQL
Great! Thanks! I'm trying to get directly the point clouds inside Instant Meshes. It seems Metashape doesn't export pointclouds in a format Instant Meshes likes, so I'm trying to open the pointcloud in Meshlab and then export it to a format readable by Instant Meshes.

The idea is not having to create the base mesh and jump directly to a Instant Meshes to build it. My kind of pointcloud is this:
Capturar.JPG
My issue is:

#1 - Sketchup handles badly complex meshes (this had to be #1)
#2 - Reshaping them to be simple box houses and more complex topography/street/tree shapes inside Sketchup isn't easy because of #1
#3 - It would be possible with something like Undet https://extensions.sketchup.com/en/cont ... t4sketchup
#4 - However it would require extensive manual work and it is subscription based, so not that cool.

So I'm modelling things manually inside sketchup with the help of Thea…

I turn the million poly mesh into a proxy, fire IR and model the box houses with IR turned on… Seems crazy, but it's pretty easy and very very fast as it's a single mesh.

In the end my texturing process is simple though. I just reimport the model into metashape and project the textures into it. It's pretty straightforward

Re: Stones scene

Posted: Thu Jul 04, 2019 12:08 pm
by DavePSB
Thanks for the info asm3d. I will have a look at metashape. I have used instant mesh several times with good results, but like you say, it doesn’t preserve uvs.

I think Meshlab has several retopo filters that do preserve uv’s, but the result is nowhere near as perfect as instant mesh. Still nice to have so many options...

By the way, if you try Meshroom, you may find that it seems to get stuck on certain nodes. All you have to do is stop the pipeline, click upon the last successful node, and execute from there. The node it gets stuck on actually completed before getting stuck, and the pipeline will zip past it and continue the pipeline.

Re: Stones scene

Posted: Thu Jul 04, 2019 12:20 pm
by samnorth
@JQL Have you tried to decimate the mesh first to something manageable inside SU or used skimp/transmutur to create a detailed proxy? I've found decimating can work well if the scan mesh is detailed enough. You can take a horizontal section through the mesh too if it's relatively flat and work on the Plan layout.

Re: Stones scene

Posted: Thu Jul 04, 2019 12:23 pm
by asm3d
JQL wrote:
Thu Jul 04, 2019 11:58 am
I turn the million poly mesh into a proxy, fire IR and model the box houses with IR turned on… Seems crazy, but it's pretty easy and very very fast as it's a single mesh.

In the end my texturing process is simple though. I just reimport the model into metashape and project the textures into it. It's pretty straightforward
Instant Meshes works only with .ply or .obj file formats. In Metashape you should create a 3D model from your cloud and then, if you want to bring it to SketchUp, you should go to "Tools > Decimate mesh" and set a low target face count (no more than 50,000 for Skp).
Furthermore, you can use this low detailed model as a proxy model for the un-decimated one.

Re: Stones scene

Posted: Thu Jul 04, 2019 3:52 pm
by JQL
Actually Sketchup goes well up to 100000 faces and can deal up to 200000. More than that is overkill. The thing is that the triangulated mesh is so hard to use in Sketchup that it's almost worthless.

However rendering the Thea mod.thea file of 10000000 poly mesh is a zip and so using T4SU Interactive Render in Sketchup with Edges allows us to build around the rendered high poly mesh fairly easily. This is something I already did with furniture, to model a simplified proxy out of an high poly mod.thea.