Help with creating a surface for my 3d object

Good morning All, I hope someone can help me figure out what i am doing wrong, I dabble with SketchUp to make custom components for my personal use, and have been messing with this object for three hours trying to figure out how why i can’t get the Surface to generate? I will be 3d printing this so, the end result needs to be 3 dimensional. Any help or guidance is greatly appreciated. I tried using “Eneroth Face Creator” but it still doesn’t generate the surface I need. Thanks!

Rear_Top_Center_Light_v1.5.skp (195.4 KB)

Fixed it for you, too tired to explain how.
Rear_Top_Center_Light_v1.5Box.skp (207.4 KB)

That one only finds edge loops that are coplanar. The surfaces your model needs are not coplanar. I used Fredo6’s Curviloft plugin to create the missing surfaces, but you can also just start “stitching” by drawing diagonals and triangles. The model also has some extra interior edges and faces that must be removed to make it 3D printable. Box was faster to post a fixed version.

Thank you so much, really appreciate it but how did you do it?

Thank you for the explanation, diagonals everywhere?

I guess he will explain it after he finishes his nap…

You only need two diagonals, since the rest of your geo is coplaner. Just go in and draw all the edges that are added in Box’s version.

And delete interior edges and faces as @Anssi told you!

Question for you. In your model it looks like you intend a shallow bevel around the rim. Is that correct?

I went through the process of modeling it from scratch to make a cleaner model and added the bevel.

Rear_Top_Center_Light_v1.5 dr.skp (91.8 KB)

Getting rid of the interior faces is important especially if you want to 3D print the thing. It’s often better to avoid creating them in the first place. With a good work flow you can do that.

If you will be modeling more things for 3D printing, you might want to start with a couple of changes. Set Display Precision higher so you can see small variations in dimensions and turn off Length Snapping.

For 3D printing it’s often a good idea to model in meters instead of millimeters. This will allow you to create fine detail more easily. If your slicer software allows you to define the units when importing the .stl file, you can leave the model at the large scale when you export. Just make sure export units are set to Model Units. Then choose millimeters or inches during import.

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Hi Dave R,

Thank for for the advice…I am just starting out with Sketchup, and can use as much pointers as possible. When i started to “draw” this i started with the “Right Side View” minus the curves, push/pull to half the length of the final dimension, then started to work on the Curves, took a while to get the Radius and everything working correctly. With everyone’s response it appears it didn’t take you any time at all to start from Scratch. I’m here to learn and not just “get” someone to do it for me, so if you could elaborate on how you started from Scratch for my better understanding. Thanks again and Happy Holidays!

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One of the “tricks” with modeling something like this is deciding where to start and what to do first, second, third, etc. I can easily think of three or four different approaches to modeling this sort of thing. In this case I started with the back as a long rectangle. I used the 2-Point Arc tool to put the radii on the top two corners and then use Push/Pull to give it thickness. New users often tend to draw a thing as if it’s entirely 2D and then try to make it 3D afterwards. This leads to problems with missing, reversed, and internal faces. I gave it the 2mm thickness before I outlined the recess just using Offset and then I pulled the outer region out to create the recessed area.

Next, I drew lines at the ends to separate the bottom front edge from the rest, used Push/Pull to pull the lower lip out and then moved the edge, shown selected) back to create the bevel on that lip. I could have pulled the face out by the shorter distance and then moved the bottom edge out a little more to create that bevel, too.

To create the bevel on the inside of the recess I drew a line defining the top of that bevel. Then I moved the line shown selected out. If you remember your high school geometry, to get a 45° bevel there, you move the line the same distance as the height up to the fold line.

Then I repeated the process on the back. You could also draw a triangle on the end and use Push/Pull to push away the waste.

Now before creating the bevel on the edge around the sides and top, I softened the edges so the lines between the curved surfaces and the flat ones aren’t visible. Then I made the thing a component and checked to see that it reports as solid in Entity Info. (It did since there are no holes or other issues.) Since you are using SketchUp 2019 and have access to the Solid Tools, I chose to make a “cutter” for the bevel. This involved using a profile (in green) and a path (the invert U-shape shown in blue.) I put in guidelines to show the alignment and the angle of the edge of the “cutter”.

After running Follow Me, I created a component of the cutter, making sure it was also solid. You could be using groups but for a number of different reasons I prefer components.

I moved the “cutter” into place against the light housing and then used Subtract to subtract the cutter from the housing to leave the bevel. I used Subtract from Eneroth Solid Tools because it respects components. The native Solid Tools will convert components they modify into groups. Not a big deal if you are using groups instead of components but if you have used components for a reason, Eneroth Solid Tools or Bool Tools 2 are better choices.

And after Subtract it’s finished business.

Edit to add: A couple of notes here. At no time did I do anything in the modeling process that resulted in holes or internal faces so I never had to worry about fixing those sorts of problems. There were never any exposed back faces once I had the shape 3D. Face orientation is important for 3D printing as that tells the slicer which side of the face gets the printing media and which side is air. I also erased coplanar edges as I went along.

Another option might be like this. Base and back, profile of the sides and top for Follow Me, then add in the inner and outer bevels.


No need for any further explanation from me.

Hi DaveR,

Thank you very much for the detailed explanation. Appreciate it very much.