Worainu
New Member
I figure I'd post this for anyone to simplify the process of cutting holes in helmets and armor (really any 3d file) using one of the most powerful free tools out there (blender). Its not super hard and its pretty useful stuff to know if you don't like cutting holes with power tools.
There are really two different ways of cutting, utilizing basic shapes or pre-built geometry.
Our first method is the simpler of the two I'm going to make a circular hole in the side of the helmet for an attachment.
Method 1 Basic shapes (easy)
1. (creation) First thing I'm going to do is add a simple cylinder object using the 'add' command in the top left that will act as a sort of 3d punch on the helmet.
One thing to note is when making objects you can change the detail it is called upon with in the lower left corner of the window.
For this example I'm going to go for a reasonable amount of detail with 155 verts. Its also important to note the dimensions of the object in question, you can change it here in this step or manually later. for this I'm going to make the radius 6.1 to make the overall diameter 12.2. Depth can matter if you are cutting a precise hole that another part (aka magnets) is going to fit into. For now I'm just going to leave that as default and continue on to the next step.
2. (translation) Now I am going to move and rotate our newly created punch to the the position I want the hole In our volant helmet here.
The shortcuts for these are g(grab or move) r(rotate) and s(scale). You can isolate the dimension you want to translate by pressing the y,x or z keys after using the shortcuts or you can do this manually with the simple translation tools on the left. I use this to lengthen my cylinder without changing its radius in either dimension.
I'm also going to lengthen our punch to encapsulate the whole of the area I want punched out. Its important to reach past the areas you are cutting unless you are just looking to make an indention in the part.
3. (boolean) Now we are going to change our selection back to our volant helmet and then use a boolean modifier to cut the hole. Headcase.001 is what my helmet is called in the scene outliner. The scene outliner is the list like window to the top right of the default layout.
Now we head down to the properties panel below the scene outliner (assuming that your using default layouts) this is where we will find the modifiers tab, It is the tab with the little wrench icon.
Now we are going to click 'add modifier' and select 'boolean' you might have to type it out to find it but its in the 'generate' subtab.
After you have the boolean modifier on our object we wish to cut a hole into you must select our punching object from the 'object' submenu of the boolean operation, you can do this by using the dropdown list but I'm going to use the easier method of using the eyedropper to select my punch directly in the scene.
Once its selected we are going to make sure that the 'Difference' mode is selected then hit apply to cut our hole. Apply is hidden in the little dropdown next to the camera icon.
Once thats done our helmet is punched. We can hide our punch and see our new piercing, so cute.
Thems the basics of boolean operations you can use any object so long as its manifold to cut shapes out of other object.
Method 2 Pre-uilt geometry (heroic)
Now its time for a more elaborate way of cutting precise holes using our objects built in geometry. This requires a model with high amounts of detail, thanks again titlewavedesign for this sick model.
For this Example I'm going to make some venilation holes on top of our volant here where there are some nice concentric indention's.
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Step 1 (Scouting/Separation) First thing to do is to have our detailed object (the helmet in this case) selected, we are then going to go into the edit mode of blender you can do this by hitting tab or clicking the editor option in the mode menu located at the top right of the default layout window.
This should make our vertices and faces highly visible as shown
I'm now going to select every face I'm wanting to create a hole from, to do this you wanna make sure you have face select active, you could use vert or edge mode but it will take you much longer to complete the current task if you do that. Our selection mode is on the top right near our mode menu dropdown. Dot is vert, line is edge, and square is face.
With every face selected I'm going duplicate our selected faces by pressing 'shift+d' then immediately clicking without moving the mouse at all!!! If you move the mouse the geometry will follow and that's not ideal for this operation. Now that our geometry is duplicated we need to separate it by pressing p and then clicking on the 'selection' option
This should isolate what we just made into a new object that we will further edit. To view this go back to object mode using the mode selector in the top left and select the newly created objectname.00x this separation shares the name of the object we separated it from.
Step 2. (Punch Building)
With the separated part selected in object mode we are going to go back to edit mode to modify our new advanced punch.
I do this by selecting all the faces and extruding them outward, making some new rectangular prism esc shapes. To Extrude you can either select the extrude function from the left in the editor tools or just hit E and drag with your mouse to your desired size.
Its helpful to have the object you are punching visible while you do this so you can see firsthand if anything is clipping weird as for this model I have some clipping near the inside of the vents so I'm going to scale each of our newly extruded regions down a bit.
I do this by scaling each section down individually.
This is a case specific order of operations, for a single hole you should just have to scale you uhh... one single hole lol. I don't have the other sections selected on purpose because it will scale based of the average of whats selected in edit mode.
After I'm done scaling all our punches I'm going to go underneath to extrude our punch through our model. You might need to hide the object we are cutting through to see our punches bottom. This is to poke through our model similar to what we did earlier with the cylinder.
Again you want to make sure your poking all the way though to make a through hole not an indention.
Step 3. (Boolean)
With our punch created we are going to go back to object mode and select our helmet file (or whatever file is being cut) again.
we are now going to go back down to the right to our properties window and click on the modifier tab(the wrench)
select 'add modifier' 'generate' boolean' or just type boolean in the modifier search
in the boolean tab object reference select our newly made punching object I like using the eyedropper but the list works too
Make sure difference is the boolean mode we are using then hit apply in the drop-down arrow tab next to the boolean modifier.
You should be home free, hide your punching object and stare at your newly acquired holes!
Blender Booleans are a powerful tool whether in simplest form or in a semi advanced use case you can come up with some nice modifications for your files without even getting out the powertools. Every mod to this file was done using these operations and variations of them.
Here are some common problems you may encounter with this workflow:
Common problems: wrong obj selection when creating boolean modifier, wrong obj selection when editing. accurate selection is key, blender works in a way where you MUST select the object you are wanting to work on physically in object mode before any operations will be correctly applied. Once you understand this it makes blender much less confusing.
Strange deformity when extruding, Again this is a selection problem, usually a random wanted or unwanted face isn't is or isn't selected you hit e. Check your sides and the bottom of your model to make sure you didn't select some geometry in an unrelated position.
Sometimes extremely polydense complex geometry isn't worth using in the 2nd method so you may need to create a mesh closely resembling it which I could cover in another post but its a little time-consuming you typically will never see this as polycounts in prints are relatively low most times.
Advanced problems: Non manafold geometry/ booleans this is much harder to troubleshoot or diagnose I recommend looking up a guide on manafold geometry, or if you have this issue with a specific obj find one that doesn't have this issue.(else you will be playing vertices whack a mole)
There are really two different ways of cutting, utilizing basic shapes or pre-built geometry.
To show this I'm going to be cutting some auxiliary and ventilation holes in a volant helmet file made by titlewavedesigns go check him out he makes great stuff.
Simple groundrules for movement in blender before we get started. MiddleMouse+Drag rotates you around your scene. Shift+Middlemouse+Drag pans you around your scene. Ctrl+Middlemouse+Drag zooms you in and out of your scene (scroll does this as well but its not very smooth)Our first method is the simpler of the two I'm going to make a circular hole in the side of the helmet for an attachment.
Method 1 Basic shapes (easy)
1. (creation) First thing I'm going to do is add a simple cylinder object using the 'add' command in the top left that will act as a sort of 3d punch on the helmet.
One thing to note is when making objects you can change the detail it is called upon with in the lower left corner of the window.
For this example I'm going to go for a reasonable amount of detail with 155 verts. Its also important to note the dimensions of the object in question, you can change it here in this step or manually later. for this I'm going to make the radius 6.1 to make the overall diameter 12.2. Depth can matter if you are cutting a precise hole that another part (aka magnets) is going to fit into. For now I'm just going to leave that as default and continue on to the next step.
2. (translation) Now I am going to move and rotate our newly created punch to the the position I want the hole In our volant helmet here.
The shortcuts for these are g(grab or move) r(rotate) and s(scale). You can isolate the dimension you want to translate by pressing the y,x or z keys after using the shortcuts or you can do this manually with the simple translation tools on the left. I use this to lengthen my cylinder without changing its radius in either dimension.
I'm also going to lengthen our punch to encapsulate the whole of the area I want punched out. Its important to reach past the areas you are cutting unless you are just looking to make an indention in the part.
3. (boolean) Now we are going to change our selection back to our volant helmet and then use a boolean modifier to cut the hole. Headcase.001 is what my helmet is called in the scene outliner. The scene outliner is the list like window to the top right of the default layout.
Now we head down to the properties panel below the scene outliner (assuming that your using default layouts) this is where we will find the modifiers tab, It is the tab with the little wrench icon.
Now we are going to click 'add modifier' and select 'boolean' you might have to type it out to find it but its in the 'generate' subtab.
After you have the boolean modifier on our object we wish to cut a hole into you must select our punching object from the 'object' submenu of the boolean operation, you can do this by using the dropdown list but I'm going to use the easier method of using the eyedropper to select my punch directly in the scene.
Once its selected we are going to make sure that the 'Difference' mode is selected then hit apply to cut our hole. Apply is hidden in the little dropdown next to the camera icon.
Once thats done our helmet is punched. We can hide our punch and see our new piercing, so cute.
Thems the basics of boolean operations you can use any object so long as its manifold to cut shapes out of other object.
Method 2 Pre-uilt geometry (heroic)
Now its time for a more elaborate way of cutting precise holes using our objects built in geometry. This requires a model with high amounts of detail, thanks again titlewavedesign for this sick model.
For this Example I'm going to make some venilation holes on top of our volant here where there are some nice concentric indention's.
Step 1 (Scouting/Separation) First thing to do is to have our detailed object (the helmet in this case) selected, we are then going to go into the edit mode of blender you can do this by hitting tab or clicking the editor option in the mode menu located at the top right of the default layout window.
This should make our vertices and faces highly visible as shown
I'm now going to select every face I'm wanting to create a hole from, to do this you wanna make sure you have face select active, you could use vert or edge mode but it will take you much longer to complete the current task if you do that. Our selection mode is on the top right near our mode menu dropdown. Dot is vert, line is edge, and square is face.
With every face selected I'm going duplicate our selected faces by pressing 'shift+d' then immediately clicking without moving the mouse at all!!! If you move the mouse the geometry will follow and that's not ideal for this operation. Now that our geometry is duplicated we need to separate it by pressing p and then clicking on the 'selection' option
This should isolate what we just made into a new object that we will further edit. To view this go back to object mode using the mode selector in the top left and select the newly created objectname.00x this separation shares the name of the object we separated it from.
Step 2. (Punch Building)
With the separated part selected in object mode we are going to go back to edit mode to modify our new advanced punch.
I do this by selecting all the faces and extruding them outward, making some new rectangular prism esc shapes. To Extrude you can either select the extrude function from the left in the editor tools or just hit E and drag with your mouse to your desired size.
Its helpful to have the object you are punching visible while you do this so you can see firsthand if anything is clipping weird as for this model I have some clipping near the inside of the vents so I'm going to scale each of our newly extruded regions down a bit.
I do this by scaling each section down individually.
This is a case specific order of operations, for a single hole you should just have to scale you uhh... one single hole lol. I don't have the other sections selected on purpose because it will scale based of the average of whats selected in edit mode.
After I'm done scaling all our punches I'm going to go underneath to extrude our punch through our model. You might need to hide the object we are cutting through to see our punches bottom. This is to poke through our model similar to what we did earlier with the cylinder.
Again you want to make sure your poking all the way though to make a through hole not an indention.
Step 3. (Boolean)
With our punch created we are going to go back to object mode and select our helmet file (or whatever file is being cut) again.
we are now going to go back down to the right to our properties window and click on the modifier tab(the wrench)
select 'add modifier' 'generate' boolean' or just type boolean in the modifier search
in the boolean tab object reference select our newly made punching object I like using the eyedropper but the list works too
Make sure difference is the boolean mode we are using then hit apply in the drop-down arrow tab next to the boolean modifier.
You should be home free, hide your punching object and stare at your newly acquired holes!
Blender Booleans are a powerful tool whether in simplest form or in a semi advanced use case you can come up with some nice modifications for your files without even getting out the powertools. Every mod to this file was done using these operations and variations of them.
Common problems: wrong obj selection when creating boolean modifier, wrong obj selection when editing. accurate selection is key, blender works in a way where you MUST select the object you are wanting to work on physically in object mode before any operations will be correctly applied. Once you understand this it makes blender much less confusing.
Strange deformity when extruding, Again this is a selection problem, usually a random wanted or unwanted face isn't is or isn't selected you hit e. Check your sides and the bottom of your model to make sure you didn't select some geometry in an unrelated position.
Sometimes extremely polydense complex geometry isn't worth using in the 2nd method so you may need to create a mesh closely resembling it which I could cover in another post but its a little time-consuming you typically will never see this as polycounts in prints are relatively low most times.
Advanced problems: Non manafold geometry/ booleans this is much harder to troubleshoot or diagnose I recommend looking up a guide on manafold geometry, or if you have this issue with a specific obj find one that doesn't have this issue.(else you will be playing vertices whack a mole)
Let me know if you have any other questions or other tips to share.
