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Bug, Feature, or Pure Artifact, does not exist in the real world so leave me alone? (by E A)
Total newbie speaking. Be kind! :)
My hat is off to the programmers and contributors to this project. You have my Respect for your talents. This/these questions are posed to help me understand the nuances of utilizing this resource.
My question is likely because:
1. SS is my first parametric CAD experience.
2. No 3D printing experience.
3. No CAD or CAM experience.
To familiarize myself with SS I decided to draw a cavity mold for a $2, 2 oz fishing weight. I know I could by a 3 cavity mold for $50 or less, but still, not a bad project.
Bank weights are basically a hexagonal rod with a profile and a flat ring to attach line. The flat faces minimize rolling in a current, and the profile helps minimize hanging on obstructions in the water.
First thing I read over and over again in SS tutorials, here in the forum, and elsewhere goes something like, "...gives you the ability to rotate/translate an extrusion or rotate a sketch and then extrude." My experience tells me this is not so, but does it really matter? Here is why.
I am concentrating with rotating here because that is the tool I have pushed possibly beyond its limits.
My methodology--at least first methodology:
1. Draw 1/6 of a weight (one of 6 identical sections of the hexagon.
2. Rotate that section around the longitudinal axis. Three total, two sided, and aligned to form a half weight body with two axial points and a pair of perimeter points coincidental to form a solid (using union as the as the uniting method).
3. Create a half thickness line hole solid,
4. Assemble the two components as a union (thanks Paul, for the suggestion).
5. Extrude a mold half.
6. Embed the half weight in the mold half with the back half of the weight flush with the surface of the mold half and do a difference extrusion to leave a cavity.
Step 6 failed (maybe). there were 4 planes left (the "married" planes of the 3 wedge objects). I realize they are most likely artifacts, but I do not know if a printer or machine would sense them or honor their existence. I do know they have special status in that they can be selected, but cannot be deleted.
Step 4 required a gap of 6/1000 to produce a final solid with no naked edges. I think I have determined this to be a "bulge" caused by the rotating process at the axis of rotation. I can visualize this happening due to "tolerances" built into the process to allow the algorithms so simulate co-incidence. I have no idea if in fact that is what is going on, though.
Both failures were finally resolved by creating one solid for the entire faceted half weight, and rotating the profile sketch to each be extruded to remove material to achieve the faceted profile.
My take on this is it would be nice if a "union" would dissolve (remove) embedded planes, "difference" would transfer an embedded surface, "assemble" would respect surfaces and not allow embedding, and "intersection" Would create a surface wherever two solids intersected.
Once again, I do not know enough to even be sure if I am seeing bugs, features, or making a big ado about something that is not worth looking at.
I will gladly upload at least the successful files if anyone has a desire to look at them, and I may have versions of failed methods that survived the purge of maybe 30 failed attempts.
My hat is off to the programmers and contributors to this project. You have my Respect for your talents. This/these questions are posed to help me understand the nuances of utilizing this resource.
My question is likely because:
1. SS is my first parametric CAD experience.
2. No 3D printing experience.
3. No CAD or CAM experience.
To familiarize myself with SS I decided to draw a cavity mold for a $2, 2 oz fishing weight. I know I could by a 3 cavity mold for $50 or less, but still, not a bad project.
Bank weights are basically a hexagonal rod with a profile and a flat ring to attach line. The flat faces minimize rolling in a current, and the profile helps minimize hanging on obstructions in the water.
First thing I read over and over again in SS tutorials, here in the forum, and elsewhere goes something like, "...gives you the ability to rotate/translate an extrusion or rotate a sketch and then extrude." My experience tells me this is not so, but does it really matter? Here is why.
I am concentrating with rotating here because that is the tool I have pushed possibly beyond its limits.
My methodology--at least first methodology:
1. Draw 1/6 of a weight (one of 6 identical sections of the hexagon.
2. Rotate that section around the longitudinal axis. Three total, two sided, and aligned to form a half weight body with two axial points and a pair of perimeter points coincidental to form a solid (using union as the as the uniting method).
3. Create a half thickness line hole solid,
4. Assemble the two components as a union (thanks Paul, for the suggestion).
5. Extrude a mold half.
6. Embed the half weight in the mold half with the back half of the weight flush with the surface of the mold half and do a difference extrusion to leave a cavity.
Step 6 failed (maybe). there were 4 planes left (the "married" planes of the 3 wedge objects). I realize they are most likely artifacts, but I do not know if a printer or machine would sense them or honor their existence. I do know they have special status in that they can be selected, but cannot be deleted.
Step 4 required a gap of 6/1000 to produce a final solid with no naked edges. I think I have determined this to be a "bulge" caused by the rotating process at the axis of rotation. I can visualize this happening due to "tolerances" built into the process to allow the algorithms so simulate co-incidence. I have no idea if in fact that is what is going on, though.
Both failures were finally resolved by creating one solid for the entire faceted half weight, and rotating the profile sketch to each be extruded to remove material to achieve the faceted profile.
My take on this is it would be nice if a "union" would dissolve (remove) embedded planes, "difference" would transfer an embedded surface, "assemble" would respect surfaces and not allow embedding, and "intersection" Would create a surface wherever two solids intersected.
Once again, I do not know enough to even be sure if I am seeing bugs, features, or making a big ado about something that is not worth looking at.
I will gladly upload at least the successful files if anyone has a desire to look at them, and I may have versions of failed methods that survived the purge of maybe 30 failed attempts.
(no subject) (by ruevs)
If you attach your model(s) I (and probably other people) will give you suggestions. If some of the failed attempts survived they will be interesting.
It's hard to say just from the description why they failed.
It's hard to say just from the description why they failed.
Attached files for at least one failed attempt with notes (by E A)
Files included:
HalfWeight2.slvs Error Free. 1/6 of the "barrel"of the weight.
HalfWeight3.slvs Error Free through rotation. Note that errors are introduced only after extruding the weight marking and then in areas least likely to be affected by this operation. Also note that to allow extruding this marking, I manually segmented the outline and removed the original. I am a little surprised that a 3D program uses outline fonts instead of functional 3D fonts--but this is most likely not the first time this thought has been put forward. these can be eliminated by forcing to 3d mesh.
AssembledHalfWeight.slvs Note that after linking, HalfWeight3.slvs has a single plane on the bottom vs the 2 planes seen in the original file.
LineHole2.slvs Error free when forced to triangle mesh. This file is still in use, it has extruded construction points to allow precise positioning. by changing the final extrusion dimension in this file, I can control to 1/1000 mm the spacing of the assembled parts in the AssembledHalfWeight.slvs.
I will upload a later set of files tomorrow.
HalfWeight2.slvs Error Free. 1/6 of the "barrel"of the weight.
HalfWeight3.slvs Error Free through rotation. Note that errors are introduced only after extruding the weight marking and then in areas least likely to be affected by this operation. Also note that to allow extruding this marking, I manually segmented the outline and removed the original. I am a little surprised that a 3D program uses outline fonts instead of functional 3D fonts--but this is most likely not the first time this thought has been put forward. these can be eliminated by forcing to 3d mesh.
AssembledHalfWeight.slvs Note that after linking, HalfWeight3.slvs has a single plane on the bottom vs the 2 planes seen in the original file.
LineHole2.slvs Error free when forced to triangle mesh. This file is still in use, it has extruded construction points to allow precise positioning. by changing the final extrusion dimension in this file, I can control to 1/1000 mm the spacing of the assembled parts in the AssembledHalfWeight.slvs.
I will upload a later set of files tomorrow.
(no subject) (by Andrew)
I had a play with your problem, and attache my solution, as FishingWeight. which may vary from your desired dimensions. I produced the weight section from a triangular extrude, and two shapes for the cutting extrude. I produced linehole as a shaped ring, without any cutout. I made the halfweight in weight2, and some explanation is needed.
The weight section extrude group should be left visible, as the lines are needed for the assembly operation. Having brougt in the section a rotation is used to make the half weight, and the angle between two section is set to 0. I first tried constraining two points to be coincident, but this required "!allow redundant constraints" to work, while setting the angle to zero did not. Turning the linering addition into a union rather than an assembly requires "Force NURBS...".
I cannot figure out a way of cutting the recess into linehole, but it is noit needed as a union works with intersecting bodies.
Exporting the assembly causes an error report on the export, as does exporting the union version. However these can be ignored as Prussaslicer (I assume you intend a 3d print for making a plaster mold).
The weight section extrude group should be left visible, as the lines are needed for the assembly operation. Having brougt in the section a rotation is used to make the half weight, and the angle between two section is set to 0. I first tried constraining two points to be coincident, but this required "!allow redundant constraints" to work, while setting the angle to zero did not. Turning the linering addition into a union rather than an assembly requires "Force NURBS...".
I cannot figure out a way of cutting the recess into linehole, but it is noit needed as a union works with intersecting bodies.
Exporting the assembly causes an error report on the export, as does exporting the union version. However these can be ignored as Prussaslicer (I assume you intend a 3d print for making a plaster mold).
(no subject) (by E A)
@Andrew
Just starting to look at your attempts. From your message, you are running into the same issues I am. I got busy with real world issues for a few days, so sorry for the delay in responding. I had achieving a successful final version. I thought. I saved it, then 3 days later, I analyzed it again and issues appeared. My memory is not identic, but they had not been there 3 days prior I am very sure. I have noticed this before. No errors, save and error upon reload. Mind you they are minor errors (nurbs to triangles or redundant constraints sort of things), but the only way I have of viewing an stl file is in Blender, and that is the only reason I have ever used it, and I am NOT proficient in Blender!
The linehole issue is the reason for the indention in linehole2. there was no flat surface for attachment, embedding the weight into the linehole made the geometry blow up when in union.
I am attaching the newest/most successful version (I still cannot get rid of 8 - 20 naked edges when creating the negative cavity! example included).
I am going to look at your work closely. Scaling will always be an issue, but, as drawn, my final version is 2 ounces to the gram if cast in pure lead. FYI lead is ~.400 ounce/cubic cm, so I will have to play with test prints to achieve 2.5 ml water displacement per half weight.
the main thing I have discovered is that SS is more or less parametric. my original issue in this thread (remaining empty planes) is that setting a dimension to lie on a plane will not remove the plane. Only a direct program constraint to the plane will do that.
Just starting to look at your attempts. From your message, you are running into the same issues I am. I got busy with real world issues for a few days, so sorry for the delay in responding. I had achieving a successful final version. I thought. I saved it, then 3 days later, I analyzed it again and issues appeared. My memory is not identic, but they had not been there 3 days prior I am very sure. I have noticed this before. No errors, save and error upon reload. Mind you they are minor errors (nurbs to triangles or redundant constraints sort of things), but the only way I have of viewing an stl file is in Blender, and that is the only reason I have ever used it, and I am NOT proficient in Blender!
The linehole issue is the reason for the indention in linehole2. there was no flat surface for attachment, embedding the weight into the linehole made the geometry blow up when in union.
I am attaching the newest/most successful version (I still cannot get rid of 8 - 20 naked edges when creating the negative cavity! example included).
I am going to look at your work closely. Scaling will always be an issue, but, as drawn, my final version is 2 ounces to the gram if cast in pure lead. FYI lead is ~.400 ounce/cubic cm, so I will have to play with test prints to achieve 2.5 ml water displacement per half weight.
the main thing I have discovered is that SS is more or less parametric. my original issue in this thread (remaining empty planes) is that setting a dimension to lie on a plane will not remove the plane. Only a direct program constraint to the plane will do that.
(no subject) (by E A)
@Andrew
Nice job. I see that you encountered much the same issues that I did.
If I select analyze/show naked edges, I see 119 problematic edges. My problem is tht even though file/export triangle mesh (an stl file), the program will report a failure, but create an stl file. I simply do not know if the file is valid. I know that the more "bad" edges it finds, the larger the stl file is, I simply do not know if it is a problem when it comes to printing.
You might find the last set of files interesting. I started with a half round blank and rotated the profile, then extruded each one. The effective difference is that you do not have 6 planes meeting at a single point at each end of the weight (ends of the axis of rotation of the three wedges). I am wondering if the code possibly offsets each point 1 mil so that each point is essentially coincident, but actually they are dimensionally distinct by a delta. I would have to analyze the points in an slvs file to determine that and it would be a task! Easier to ask on of the coders!
Nice job. I see that you encountered much the same issues that I did.
If I select analyze/show naked edges, I see 119 problematic edges. My problem is tht even though file/export triangle mesh (an stl file), the program will report a failure, but create an stl file. I simply do not know if the file is valid. I know that the more "bad" edges it finds, the larger the stl file is, I simply do not know if it is a problem when it comes to printing.
You might find the last set of files interesting. I started with a half round blank and rotated the profile, then extruded each one. The effective difference is that you do not have 6 planes meeting at a single point at each end of the weight (ends of the axis of rotation of the three wedges). I am wondering if the code possibly offsets each point 1 mil so that each point is essentially coincident, but actually they are dimensionally distinct by a delta. I would have to analyze the points in an slvs file to determine that and it would be a task! Easier to ask on of the coders!
(no subject) (by Andrew)
PrusasSlicer made auto-repairs to the STL I created, and sliced the result without any issues. Meshlab found and removed duplicate vertices, and the model was fine. I was also able to successfully slice the model using Cura. It is always worth trying the exported file which has reported errors, as so far Prusaslicer has been able to repair all of them that I have tried.
(no subject) (by E A)
@ Andrew
Yup, after reading what you sued, I installed PrusaSlicer on my linux machine and gave it a test. It was able to correct all of the SS files I tried. thanks for the tip!
Granted, the most recent snap I could find for it was 2.1, but if I remember correctly, Prusa's latest stable is only 2.5, so that is not too bad and it sliced that mold top file in about ummm..too quick to measure.
What part of the world are you in, Andrew? I am north of Dallas on the Texas / Oklahoma border.
Yup, after reading what you sued, I installed PrusaSlicer on my linux machine and gave it a test. It was able to correct all of the SS files I tried. thanks for the tip!
Granted, the most recent snap I could find for it was 2.1, but if I remember correctly, Prusa's latest stable is only 2.5, so that is not too bad and it sliced that mold top file in about ummm..too quick to measure.
What part of the world are you in, Andrew? I am north of Dallas on the Texas / Oklahoma border.
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