Manifold Solid Problems for a Laser Cut Site Model
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Hey there,
I'm relatively new to SketchUp, but have been getting along pretty well. I'm currently trying to use the plugin Slicer5 to convert a SketchUp site model I have into pieces which can be laser cut.
The problem I'm having is though that I can't seem to make it into a manifold solid. Where the buildings are meeting the terrain I can't seem to get them to make a solid. I've tried drawing edges along them, but Solid Inspector is still highlighting them all as errors.
Does anyone have any tips on how to make this work?
Thank you.
p.s. I've attached the file, in case that helps.
1 to 1250 Furnace Hill Site Model Closed With Base Edges Need Fixing.skp
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Hi Holly,
A lot of them do not have a bottom face (or the face at the bottom is outside the component - just cut and paste in place inside the component to fix it). Then there are components with inner faces and edges that create unnecessary geometry. There is not a general rule of thumb for these errors in your model but you will need to go through one by one to see what the problem is.
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A manifold solid has the following properties...
It is a group or component that contains only faces and edges - no nested groups etc [it can contain guide lines/points as these are non interactive with any geometry]
In addition to the faces/edges rule... every edge must have two faces - no fewer and no more.
So that means no unfaced edges, no flaps, no 'holes' in surfaces, no internal 'partition' faces where an edge can have three or more faces, and no shapes meeting with a shared edge - like two boxes touching at an edge that could then have an edge sharing four faces.Why not slice the base-terrain and then the buildings separately - rather than trying to merge all of the bits into a single solid and then slicing...
You need to regroup everything into just two separate groups [that are both solids] and try the keep the 'terrain' simple...Thomthom's SolidSolver will highlight issues but if you leave nested groups it'll never be fixable !
Slicer5 needs a manifold solid, the older Slicer[~4] doesn't... but that can cause weird results too [still available...]
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Thank you, both. I thought of slicing them seperately, but my buildings intersect the terrain. Is there a way to make there bases follow the terrain?
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What's been said before about making the separate groups 'solid' etc stands...
Group the terrain and keep the building as separate groups
Remove internal partitions etc...
Make sure the terrain group in a solid.Edit each building group in turn.
Remove the base face[s].
Install mt Extrude tool set...
Use EEbyVectorToObject to pull its preselected bottom edges down vertically through the terrain, they should trim to it.
Repeat for all buildings.
Now the building won't be 'solids' [no base] but they are ready for merging with the terrain.
Edit the terrain group and select its top surface.
Context-menu > Intersect with Model...
Now the bottom edges of each building should have their outlines replicated on the terrain.
To see this more clearly use View > Component Edit > Hide Rest of Model... to toggle on/off the buildings visibility while in the group edit...
If there are missing edges [possible if very small because of SketchUp's limitations on creating ting geometry...] add them manually by tracing along a building's edge onto the terrain surface.
When you have got a set of outlines added to the terrain surface select the inner form and delete the face.
Now you should have a set of building groups with open bottoms that extend down to the terrain's surface, and a terrain with holes in it representing each building's bottom edges.
Explode all of the groups inside one big group to merge the geometry.
With any luck the merged geometry will form a solid - reported by Entity Info.
If not, then use SolidInspector to find the problems and fix them manually... -
I've finally managed to make my site model into a manifold solid but when I try to use Slicer5 with the settings of spacing and thickness being 3mm (for 3mm MDF) SketchUp crashes. Is there any reason why this would happen?
Many thanks,all of your posts have been really helpful.
Holly
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OK now the next issue...
SketchUp can't cope with the creation of very tiny edges/facets.
It's built to model 'buildings' and all of their related accompaniments - up and down from that - so objects <0.1mm or >1km will ofeten cause issues...
I should have guessed from the '1 to 1250'
If you are making 3mm slices though a small object some of them will probably fail because they are so tiny that SketchUp considers them to be non-existent because their starts and ends are so close together ! These issues occur in native tools as well as API based scripts... Try doing a native FollowMe on a tiny face around a small/tight bend - you'll get missed facets etc...
In SketchUp you should usually model at 'full-size' which can avoid many of these issues...
Later on scaling a larger object downwards will work - because tiny facets can exist BUT it's initially making them that is the issue...Here's my suggested fix...
[Work on a copy of your SKP!]
Let's say we'll scale this up x100 and retry...
Draw a line 10mm long.
Use the Tapemeasure tool and pick the two ends of the line in turn, the VCB should say '1'.
Type 1000mm at the keyboard [i.e. x100 bigger].
You are prompted to rescale the model.
Answer Yes.
Zoom Extents to see what you have.
Now your model is x100 bigger and far less likely to mess up when Sliced [or even when any native tool is used on tiny geometry!]
Do the Slicing - making the spacings/slice thickness x100 more to account for the temporary rescaling of the model...
When it's done you now use the Tapemeasure tool, picking on the same line... but this time you type in 10mm and scale it back down...The tiny facets will now remain - they can exist but it's making them that can prove difficult...
Report back...
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