# Mapmaking Discussion & Philosophy (WIP/Critique) > Building/Structure Mapping >  WIP-Renaissance forts-Awhayji Resources

## 4maram

Hi, here's the main base for a Renaissance-style fort.

It's part of a project world that I'm developing. It will be in the Renaissance age, and with that type of technology, you need forts noticeably different from the usual medieval castle.

This has been done with pen paper and a ruler, and represents a 4 points fort.



It represents 6 levels of height:
-0 Moat
-1 covered outer round and parade 
-2 curtain-defending batteries
-3 glacis (esplanade at the bottom)
-4 bastions
-5 top of the main wall

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## Redrobes

Ohh nice map and interesting technique ! I think my first time seeing something like that done with traditional drafting rulers. Do you colour the shapes in or remove the construction lines later on ? Well I guess I will have to see this one progress.

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## Adfor

The approach is genius. I appreciate the symmetry, and the traditional ruler technique that created it, well done. Interested to see further progress.

IR

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## 4maram

Here's the fort without the building lines, and some other detail, like the passages to get to the curtain-defending batteries or the ramp to get to the bastions. They have to be wide enough so that when the fort is built, the defenders can fit the cannons through them to their final places.



You may notice some simetric aberration. That is because it's not the original, but a copy, and I don't have square and bevel here.

I may make an elevation sketch and maybe a proyection from one of the corners and from a high point of view, but I'll keep it as clean as possible to ease the making of copies, so no coloring.

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## 4maram

I redicovered SketchUp and had some free time so I made a model of the fort in 3D.




















Okay, If I'm going to be honest, I found some plans of the Castillo de San Luis de Bocachica, and reverse engineered it's geometry, and made the model. Here's the original:  look at the first page

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## 4maram

I'd like to add cannons and (gah! english lexic is so limited!) merlons for cannons (in spanish: cañonera (not the gunboat, the fortification element)) but, while on paper it wouldn't take long, on the program it will begin to act up, erasing parts of wall and more things, so I'm not making them.

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## 4maram

Here's another image showing the scale of this fort. It's HUGE.



Those black spots indicated with red arrows are people.

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## ChickPea

This is a cool project! Nice work so far.

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## - JO -

Nice work !

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## 4maram

Now I'm making a 5 points fort, basing it off the 5 points fort at Jaca, Spain.
Now is still a bit blurry but I'll be able to clear it enough with some time.



Am I the only one who sees also a flower there?

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## 4maram

Sorry for those expecting the 5 points fort, I had to delete the file because the measures were in feet and inches instead of meters, and passing from meters to feet and inches has generated iregularities in the overall design. So I have to remake it all from zero.

Also, while this project advances, I can't advance very much on the Regional map, so that one may be stalled until near the end of January, probably... Or maybe not...

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## Bindusara

a nice use of sketchup!

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## 4maram

Now, this is the good one. I've found a site where they discuss about how those forts were designed, and that the final design ended having small variations that helped on the overall defense. They also include a guide to how to draw the silhouette/level/base of a 5 points fort of the 17th century so, following that guide I'm making a 5 points 17th century fort and posting it here, some steps at a time (it only consists of 12 steps). When I finish it, I'll just continue making the fort.

Steps to draw the silhouette of a 17th century pentagonal fort (every pentagon named I'm asuming that it's a regular pentagon (maybe I should try to make an irregular fort...)):
1.- Draw a circle (no more than 500 meters in diameter to be able to support with muskets).

2.- Divide it in 5 angles of 72 degrees.

3.- Connect the points where the lines cross the circle to form a pentagon (draw the pentagon inscribed in the circumference).

4.- Divide a side of the pentagon in 5 equal parts, named: *a*,*b*,*c*,*d*,*e*, between the corners *A* and *B*. The points that delimitate the equal parts are, from left to right: *A*, *1*, *2*, *3*, *4*, *B*

5.- Draw the pentagon circumscribed to the circumference and draw a line, from the point *1* on the inner pentagon to the outer pentagon, perpendicular to the side of the pentagon. We will name that line the *flank* of the bastion.

6.- Extend the *radius*  of the inner pentagon on the corner (point *A*) we are working on, until after well passed the outer pentagon. Draw another line going from the point *3*, passing through the end of the *flank* and reaching the *radius* that goes through the point *A* and the corner of the pentagons. we will name the point of the end of the bastion point *C*

7.- Repeat on the opposite side of the corner/radius steps 5 and 6 to finish the bastion.



8.- Draw a third pentagon with its corners coinciding with the point of the bastion (*C*), and draw bastions (steps 5, 6, and 7) for the rest of the corners.

Now we almost have the usual silhouette of the poligonal fort but we must mark the *orillons*. Around here would be the emplacements where would go the cannons that defend the curtains.

9.- Cut the *flank* of a bastion with a perpendicular line *f*, dividing the *flank* in two equal halves, parallel to the line we previously divided in 5 equal parts.

10.- To draw the location on the right side of the bastion, we divide the line *a* in half with a perpendicular line and we make a rectangle/square there, from that point, to the midle of the *flank*. And then we repeat for the rest of the bastions.



11.- We erase the half of the *flank* nearest to the main wall/innermost pentagon to show the *orillon*. And then we clean up to show the final result.

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## 4maram

Here's an irregular pentagonal bastioned fort. I'm around after step 8 for regular forts, but it's a lot different for irregular ones. This is just the dirty map of the first version. I'll experiment a bit with diferent bastion forms maintaining the main wall.

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## 4maram

Here's a study of the defensive artillery placed on the regular pentagonal fort. Only 1 and a half bastions are studied (and armed with cannons) in this case.



The cannon type I'm supposing is being used are french naval cannons of 36 lbs. Its point blank range is of 650 meters (the arches shown on the image), but its maximum range is of 3300 meters (outermost circle). These cannons need a recharge time of 8 minutes after being shot.

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## 4maram

Here is how the regular pentagonal fort looks from the ground 1 km away from the center. I have developed the emplacements for cannons only on one bastion.



1: That is the fort?
2: Yeah.
1: That tiny thing over there?
2: Yup that tiny thing over there.
1: It's too low, even I could bring a ladder from home and scale it.
2: It may seem very low from here but that over there is a 6 meter wall over the ground (glacis) and there is a trench 10 meters deep and 30 meters wide before you can reach the wall, and that trench is also in the range of the defensive artillery.
1: ... and no big walls to shoot at with my artillery... It's not fair!
2: That's the purpose.

Now you may tell me "Hey 4maram, why not just copy and paste the polygons on the other bastions?". Well, Sketchup is a bit of a ... . You can't draw perfectly regular polygons here. You have to paint every single line, because, while the bastions may seem like the same, they aren't.
Well, I end my rant against the SketchUp program here (for now...).

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## 4maram

I remade the fort/citadel and spent 4 hours on it. I'm seriously beginning to consider accepting donations and payed commisions...

The citadel has a radius (from the center to the point of one of the bastions) of 250 meters and a capacity of 40 cannons.
It has a trench 10 meters deep and 55 meters wide, and a covered path 1.6 meters deep and 39 meters wide at its narrowest points (I know that the wides are disproportionate to the actual size of the citadel).
The parade is at ground level, the bastions and parapet walks are at 4 meters over ground level and the parapets are 6 meters over ground level.

The sentry boxes (in spanish: garita, garitas) aren't included, but they would be circular and of 3 meters in diameter. There would be one at the point of each bastion plus two more on the corners that join the flanks and main walls of each bastion: 3 garites per bastion.
Ramps to the bastions, a bridge and a door and inner buildings aren't included either.

Here's a top view



The openings for cannons have been carefully engineered to make sure there aren't any blind spots.
On each side of each bastion the cannon nearest to the point, can shoot in an angle of 80 (horizontal) degrees. The next shoots in an angle of 70 degrees, from the point where the outermost shooting line angle of the cannon situated behind the orillon crosses the diagonal that divides the next bastion in two simetrical sides, from that point up to 70 degrees towards the point of the bastion we are looking at. The cannon at the flank of the orillon, points from the inside of the orillon, to the point where the innermost side of the 80º opening crosses the diagonal of the next bastion.
There are no blind spots.

Here's a view zooming in and angling the camera, showing a bit of sky.



And here is a view from the groud, 679 meters away from the nearest bastion, 929 meters away from the center of the citadel.



Can somebody help me with the amount of people and professions that would be needed to maintain the fort operative?

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## Falconius

Why'd you include nooks behind the towers?

I've no idea how many people it'd take to simply maintain that fort let alone man it, but I'd imagine it'd employ quite a few.  All that masonry, that ditch and the grounds.  No access to lawnmowers.  I'd guess a groundskeeper and maybe 5-10 permanent labourers for him, probably a carpenter, a full time mason/manager guy, who'd hire laborers when needed.  If it includes stocking food and ammo, there'd be a commander, a quarter master, a master of arms, a blacksmith and possibly an armourer.  All with associated assistants and apprentices.  If it included stock it'd have to be guarded as well, which could probably done with 15-30 soldiers.  To actually garrison the place, a couple of hundred.

Edit:  I forgot about a cook.  They'd definitely have a cook and the cook would have 2-4 helpers, and if garrisoned more like 12-20.

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## 4maram

I don't understand what are you referring to when you say "nooks behind the towers".

I'll asume that you are meaning bastions for towers, and the nook bexind the tower may be two things:

1.- The emplacement for a cannon behind the orillon.
   That cannon defends the *curtain* wall, the opposite (on this curtain) *bastion* wall,  and the blind spot that can form just in front of the bastion. Here's a depiction of its angle of shooting line:



2.-The part of the bastion that connects with the path on the curtain.
   It's just there because the ramps through which the cannons and pretty much everythig that gets to to the bastions or curtains has to go through any of those ramps, that will be connected on the inner side of the corners of the curtains. To ease the travel, there's not any door.
   You may think that this is foolish, because if the enemy was able to enter the citadel there would be little to defend from there. Building something to block that possibility would make the overall defense to be less effective, up to the point where it would be worse to have that there than not having it.


About the cuantity of people needed to run the citadel. I'm already assuming that there would be needed a BIG number. no less than 500 people.

Look: 


> A 36-pounder required a 14-man crew, comprising one chief gunner, 12 gunners, and one powder-boy.


Source: https://en.wikipedia.org/wiki/36-pounder_long_gun

Suposing we put in every position available one of these guns, the minimum population required to defend the citadel would be of 14*40 = 560 people. Not counting cooks, soldiers, officers, petty officers, messengers, scouts, stables managers, etc.

This fortification won't be found in the middle of nowhere. You will find it near a city and defending a strategic spot.

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## 4maram

Here's an update to show you the angles at which the 4 guns on the side of each bastion can shoot:



And here is an update on the map of the fort. The trench and the covered path are definitely smaller (36 meters and 11 meters wide) and more proportionate to the citadel:

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## 4maram

Hello there. It's been a looong time, but I had (and still have) to study.
I was able to sneak some time for the 5Point star fort and was able to almost finish it and paint it.


Here we can see Helen at the corner of the trench of Point 1, with the external fort at her left and the bridge and drawabar bridge just behind her. Notice the cylindrical garites at the three main corners of each bastion.
I might make a rough model of a cannon to place one on each position available. This fort is designed to have at most 40 cannons (8 per bastion).
Also, notice that the top of the parapet is slightly tilted so that any shooter can place his gun over the top and rest it there while aiming.
The parapets on the inner side are 2 meters tall, and tou gould need a stepping stone to get your head and shoulders to effectively position your gun.


Here's a top view of the 5 point star fort, almost fully colored. Point 1 is the one at the right. There's an advanced fortification in front of the door side, to protect the door. However, this fortification shouldn't house cannons, so they can't be turned on the main Fort should the advanced fortification fall to the enemy.

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## IllustratedPageBookDesign

This is so cool! I love how you made the 3D versions.

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## 4maram

Hi, I've found another proyect for 3D modelling.

This is the Castle of Burgos (Spanish castle at the Spanish city of Burgos) as it was when the French (Napoleonic troops) had Spain invaded for 5 years.
During this time, the french mappers and topographers took their measures and eventually drew the map:


I'm going to cross-reference the roads shown there with the heightmap of today to make the model:

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## 4maram

Hello again.
I've found a bigger map of the fortification and it includes the surrounding city and roads, the river and a hornwerk plus ravelin to the North.



Now it's going to be easier to cross-reference the heightmap.

Also, I've found some images of a model of the castle in the period 1808-1812, that will help in the modeling of the original castle ("Donjon" in the map), here they are:


View from North to South


View from East to West


View from South to North

I couldn't find any view of the model from West to East.

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## 4maram

I could make a heightmap with the help of Google Earth:

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## 4maram

I feel like I should tell a bit about the history of this fortification.

Before the French invasion of Spain, it didn't have much strategic value, as it was in the center of Spain.

It was built in 884 during the Reconquest of the Spanish Christian Kingdoms, and it was ampliated by the following castellans.

Between at least 1042 and 1277 it served as jail of noblemen, and from 1252 to 1284 and 1390 to 1454 served as palace. (Yes, I know the periods as jail and as palace are overlapped, but one tower could serve as jail while the rest of the castle served as palace).

It saw use as stronghold in the civil war of 1474-76.

In the XVI century it was used as artillery academy and gunpowder factory.

In 1736 there was a fire that burnt the wooden decorations of the palace, made on 1252.

So, before the French invasion, it was mainly a late-medieval castle, that's the part that's recognisable nowadays.
Then came the Napoleonic invaders in 1808 and they took the castle and the city, and held it for 5 years.
Because the French were invaders, they needed to secure every strategic position they could find, so the castle and the hill was again a strategic spot in the surrounding plain.

They brought the defenses up to date in those years and they built a hornwerk and ravelin on the hill of San Miguel.
From september to october of 1812 they went through a siege by Arthur Wellesley (later known as Duke of Wellington), where the siegers (Anglo-Portuguese) went through a great number of casualties, while the sieged (French) only lost a fifth of their numbers.

Later, in june 13, 1813 the French retired from the fort, and they made it explode to avoid leaving any equipment or documents usable to the enemy.

Today what remains is part of the medieval castle.

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## 4maram

Hi, I need a KiloByte of help please. Does anybody know how to make heightmaps from the black-to-white gradient on Sketchup?

I've already tried with the Bitmap to Mesh extension for SketchUp but it gives out an error when I input the bmp file.

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## 4maram

Oh, solved, although it has blocked doing something.
Anyway, there goes the heigtmap:


Note: Yeah, I know that the terrain's Z axis is too big compared to its X axis.

It should look more like this:

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## 4maram

For anybody guessing, I'm following this tutorial here on youtube: https://www.youtube.com/watch?v=Qd2dqe3v7nU

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## Redrobes

This looks like an interesting project.

I did my tutorial on how I make height maps from drawn contours here:
https://www.cartographersguild.com/s...ad.php?t=33666

I think you have solved it now but I dont know how to get a greyscale gradient into sketchup.

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## 4maram

I used "SketchUp Make 2017" and the extension called "Bitmap to Mesh".

I got the greyscale gradient from tangrams heightmapper.



And I did the aligning phase using the lines of the streets from tangram's site and a "first stage" taken from Iberpix to get where the medieval fort was placed:



When setting the X to Z scale, I used the number that tangram's site provides.

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## 4maram

I finally finished the heightmap. Heightmaps following this tutorial are VERY slow to make if you don't have high processing power (took me 3-4 hours to wait for SketchUp to finally charge it all). anything like an intel-i7 or higher I guess should do fine.

Here are some shots:



I'm doubting between making the buildings in another file and then importing them to this one or making them directly on this file even with the slowness of moving around...

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## 4maram

Sorry for keeping the Burgos Castle at a hiatus, I was geeking all over Fort Rikasoli (Valletta, Malta).

Look at those huge geometrical walls...

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## 4maram

If you remember, some posts ago, (12-02-2020, 08:41 AM) I  talked about *irregular forts*, so I just made one and I'm releasing it here.



It has a *hornwerk* on the back-left side of the fort, and a *crownwerk* on the right side.
In front of every other side of the fort there's a *ravelin*.
The extended hill in every side is the *glacis*.

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## 4maram

If you remember the 4-bastion fort at the beginning od this thread, I'm going to make the floor plans for it.

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## 4maram

Okay, here comes an asset:

Stronghold cannon plus carriage(?) in Spanish: cureña, the place where you put the cannon. It has 5 parts:

-Parapet: it protects the cannon from the front as much as possible. It varies in thickness between locations, from 0.5 to 5 meters.

-Cannon: Cylindrical tube closed on one end. Made of iron or bronze. It shoots bullets. In this case 24-pound bullets, so it's a 24 pounder.

-Front-back-moving carriage: it's the usual rectangular piece of wood with 2 vertical sides, another vertical piece near the front, 4 wheels and 2 stump-holders, where the cannon's stumps are supported.

-Direction/Turning carriage: It's a pair of rails where the 4 wheeled carriage rests. It has between 3 and 5 crossbeams, a pivoting place and 3 wheels. It usually has some inclination, so the cannon tends to go down into the battery. The inclination helps with the recoil. At the other end of the rails there is a windlass where a chain winds to control how much down can the cannon go.

-Rails and Pivot: Is the only part of the cannon that remains after the cannon is retired or disarmed. The rails are a pair for the two front and the back direction wheels.


Asset: Stronghold cannon:

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## 4maram

One cool thing about it is that if you want to make a battery of cannons, you just put 4 or 5 times the photo, and you're done.

WATCH OUT, You will need to edit the image a bit before actually placing it down, to avoid including the black border lines of the parapet and the gray color of the background.

The parapet colors are okay for a stronghold battery.

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