Thanks for the comment Amber! If you haven't already, check out all of the PM videos I made in the playlist or on the website here: engineer4free.com/project-management Cheers :)
I'm a little confused with these dummies. I understand using a dummy in the top half for F, since the IJ numbers between D, E, and F are different. What I don't understand is using a dummy in the bottom half. Wouldn't the IJ number be different for B regardless of the dummy?
Oh yeah, so with this style, every arrow should have a unique IJ number, regardless if that arrow is a real activity, or a dummy. And because G depends on B finishing, there must be a dummy that connects the end node of B with the start node of G, so that's why the dummy is there. Hopefully that makes sense.
This is a little more helpful, but my table goes from Activity A to O and has overlapping predecessors. Im struggling to figure out how it should flow. If there is any possibility of help that would be greatly appreciated!
In a first example, why E can't finish on G node but F has a dummy? why F can not finish on a G note also same as E. My lecturer says that all activity should have a finish node. But I find that if there is no further activity like in this first example with E and F so it could finish on G node.
this question should have been asked by the guy and should have been answered in the video. We are beginners and we dont know most of the things. And it is fucking unclear
I didn't know how to put these numbers and what they refer to so it really helped thank you so much but I have a question. Do we have to draw the arcs from left to right ?? can't we draw it from above to below ??
Typically they should go from left to right, that's the convention that people use. Just like how we read from left to write, we do network diagrams from left to right.
1:14 why D and F consider as dummy activities meanwhile it was stated on the table that it happened right before G ? Can somebody help me explain this ?
What software program did you use to draw the PDM and CPM diagrams for your UA-cam presentations? I really enjoy the lessons, they are the best I have found for the subject matter.
Thank you for the video. But in first example why not connect D directly to G instead of using "dummy" because G starts when D finish as shown in the table
Hey, the nodes in this style are the points in time, whereas the arrows are the activities. Node 6 is the point in time when D is finished, and also when G begins. G does begin right when D finishes according to the diagram. The dummy that goes from 5 to 6 is there so that E and F have unique start and finish nodes compared to each other (id, don'e start and finish on the exact same nodes).The dummy allowed for the creation of node 5, which means that F finishes on node 5 rather than 6. But ultimately node 5 and 6 are the same point in time, just with a different label to help identify based on the style of this network diagram. This video is worth checking out too: www.engineer4free.com/4/introduction-to-cpm-network-diagrams
In the first example, you drew two arrows pointing to activity (6), is that okay? Isn't it supposed to be one arrow out and one arrow in for each circle (activity)?
You can have multiple arrows out of one node (going to different nodes). You can have multiple arrows in to one node (coming from different nodes). What you cannot have is more than one arrow sharing the same beginning and end node. For example, in the first problem, look at activity D. It is the only arrow that goes specifically from node 3 to node 6. No two nodes are connected directly with more than 1 arrow between them. Does that make sense? Each activity can then be labelled uniquely by just referring to the start and finish node. We call that the ij number. Activity D's ij number is 3-6. No other activity has that number.
Are you referring to the second diagram? It's because if we did that, then G and E would both have the same i,j numbers (be on the same arrow). We can't have that, so we need a dummy.
This is an Activity on Arrow (AOA) diagram. Each activity (arrow) must have a unique start node and end node (no two arrows can point from the same start node to the same end node. See videos 10-12 here: engineer4free.com/project-management
Hi, sorry for any confusion brought about by the naming of each style of diagram. There are two types of network diagrams: Activity on Node (AON) and Activity on Arrow (AOA). In these videos I usually refer to AON as PDM, and AOA as CPM. That's local lingo for me that I originally learned, but you are actually better to use AON and AOA, it's more clear.
Since we can make a decision where to put dummies, does that mean there is more than 1 correct answer in these type of questions? And also can there be no dummies when drawing these?
Yes there may be more than one right answer depending on the question. Some problems may not require dummies. The right answer(s) will have the least amount of dummies. If there is a way to draw with diagram with less dummies that you have done, then you do not have the right answer. Check out videos 10-12 here: engineer4free.com/project-management
How would i handle creating this diagram if for example activity F had no predessor? I have a hw problem with this and don't really understand how an activity so far down the list can have no predessor... thanks!
All activities with no predecessors are initial activities. Put it somewhere on the far left of the diagram near A and give them both an ES of 0. If F has some successors, just draw a really long line connecting F to it’s successors. You may need to attempt the drawing a few times to reduce crossovers. It might look stupid, but is totally possible.
In the second diagram, what is the need of a dummy arrow from B to C to make G. It can be straight instead of dummy right. I am very confused. Please help
A straight arrow between two nodes represents an activity in this style of network diagram. There is no such activity present in the table of dependencies that would go between nodes 3 and 4 (if there was it would mean there would be an activity that succeeds B and is succeeded by G). The dummy activity has to be there because it shows the dependence of G on B. Node 4 is the point in time where G starts, and node 3 is the point in time when B finishes; B must be finished by the time G starts, so hence the dummy going from 3 to 4. Watch this video: ua-cam.com/video/TDriHWnHkrE/v-deo.html it is the predecessor (lol.. bad joke) to the video that we are commenting on and explains some things. These videos are all part of a larger playlist too, you can check it out at engineer4free.com/project-management this is video #11 in the course.
Hey, not sure what you mean. There is no point in the second example where the network diagram suggests that E is dependent on B and C. Can you clarify?
Hey, I have some videos on more complcated relationships in projects, you can find them in videos 16-22 here: engineer4free.com/project-management and also some other videos on PERT which are numbers 39-46 in the same link. Should be enough to get started.
Hi i love your videos.... i am lost with my diagram that i must do... please assist on my diagram i am with E been alone and not depending on anything, is that still ok?
There can be more than one initial activity. So if activities A and E of your project for example don’t have predecessors, draw them both near the left side of the diagram, and then draw their successors coming out to the right.
Could you help figure this one out? Killing my brain over here. Activity Duration Dependent on A 3 none C 3 none B 2 A D 5 C E 2 none F 4 E G 3 D,F H 1 D,F I 2 B,G R 0 H,I
just a question when doing the first example i done it before you had completed it to see if i done it right like you i did essentially do it more or less right but i didnt have a dummy activity at all i just drew a curved arrow flowing into g is this acceptable or must i use a dummy activity
It is just a requirement of this style of network diagram that any two given nodes only have one single arrow connecting them. It gives each activity (arrow) a unique identity of which node it comes from and goes to. Because two arrows would ideally go between 4 and 6, we need to introduce the dummy node 5 so that one arrow goes from 4 to 6 and the other goes from 4 to 5.
Yeah no problem. This is an Activity on Arrow network diagram, and one of the rules about these things is that only one arrow may go between two given nodes. ie, node 4 and 6 can only have one arrow connecting them directly, not two. By doing this, we can identify any given activity (arrow) by it's i-j number, and in the case of activity E, that would be 4-6. It's just the convention, so because two activities here go between nodes 4 and 6, we need to introduce the dummy activity that gets its own node (5). Either E or F could have had the dummy, but one of them needs it in this project.
Ah yeah there is another video that I introduce the method and go a bit slower in, check it out here: engineer4free.com/4/introduction-to-cpm-network-diagrams
Hey Mafuj. I keep a current list of the hardware and software that I use at engineer4free.com/tools Its technically all hand drawn just with the aid of a drawing tablet and some video editing tricks
No problem. I'll just let you know that this video is part of a playlist though and comes after a full section on PDM network diagrams and an introductory video on CPM network diagrams. Check out the full curse at engineer4free.com/project-management I recommend watching video 10, and if you have the time, videos 1-12. They build off each other, so by the time you get to this video, you'll have sufficient exposure to this kind of stuff =)
Not really good example. Why you draw two points for one activity? This is superfluous and unnecessary actions. Why complicate if classic diagram is built with one point in one activity. Such diagram difficult to understand and harder to look.
I agree that the bottom diagram is less intuitive. However, it's a legitamite way to draw diagrams, and is taught in universities, so I have made some tutorials to help students that need to learn how it works.
👌 Got my exam in half an hour! This really helped me. Thank you! 👍
Good luck!! Hope it went well 😁
Did u pass?
@@thatdonkeymercelot6409 bro, I have no idea. I must have passed. Its been yearssssss. hehe
Bro did u pass ?
FAST, INFORMATIONAL, UNDERSTANDABLE AND QUICK
THX MAN FIRST VID I DONT NEED TO X2 (STUDY RELATED)
this is helping me with a course in my senior year in collage! my professor didn't explain it that easy way ,thank you so much!
Glad it helped!!!! =)
Got my exam in 1.5 hrs tysm 😭❤️
Oh man, those dummy arrows were kinda messing with me. Thanks for walking us through all these really good examples!
The cost of 2 Construction Management Books with little to no help. $170. The cost of 40 slides in order with step by step examples. PRICELESS thnx
UA-cam FTW 🙌
You have made project management very accessible. Thank You!
Thanks for watching and commenting Arnold!
Oh my word. This is so helpful! Thank you so very much for sharing your knowledge!
Thanks for the comment Amber! If you haven't already, check out all of the PM videos I made in the playlist or on the website here: engineer4free.com/project-management Cheers :)
Engineer4Free absolutely!! This has been a life saver while studying for the PMP exam!
Thank you so much for help. this is really helping me for my exams
Glad to hear it! You can find the rest of my PM tutorials here if you need any more: www.engineer4free.com/project-management
I'm a little confused with these dummies. I understand using a dummy in the top half for F, since the IJ numbers between D, E, and F are different. What I don't understand is using a dummy in the bottom half. Wouldn't the IJ number be different for B regardless of the dummy?
Oh yeah, so with this style, every arrow should have a unique IJ number, regardless if that arrow is a real activity, or a dummy. And because G depends on B finishing, there must be a dummy that connects the end node of B with the start node of G, so that's why the dummy is there. Hopefully that makes sense.
sir how can we know when to use dummy line ?
Thank you so much
I have my exam in 6 hours , and you taught me what my professor didn't in an entire semester (I didn't listen tbh)
Lolll. Good luck brother 🙌
This is a little more helpful, but my table goes from Activity A to O and has overlapping predecessors. Im struggling to figure out how it should flow. If there is any possibility of help that would be greatly appreciated!
Great one :). Was searching for a one to see how to resolve those errors
Awesome glad you found it! Make sure you check out engineer4free.com/project-management if you haven't already for the rest of the videos :)
In a first example, why E can't finish on G node but F has a dummy? why F can not finish on a G note also same as E. My lecturer says that all activity should have a finish node. But I find that if there is no further activity like in this first example with E and F so it could finish on G node.
this question should have been asked by the guy and should have been answered in the video. We are beginners and we dont know most of the things. And it is fucking unclear
It's not possible because starting point and end point of two arrow can't be similar.
Ur explanation is too good i understood the concept👏👏
🎉🎉
A pencil and a rubber. Most critical tools.
S’all ya need
I didn't know how to put these numbers and what they refer to so it really helped thank you so much but I have a question. Do we have to draw the arcs from left to right ?? can't we draw it from above to below ??
Typically they should go from left to right, that's the convention that people use. Just like how we read from left to write, we do network diagrams from left to right.
I see thank you so much :) :) :)
Will you please explain how to number events(nodes)?
1:14 why D and F consider as dummy activities meanwhile it was stated on the table that it happened right before G ? Can somebody help me explain this ?
finally one with activity on arc
What software program did you use to draw the PDM and CPM diagrams for your UA-cam presentations? I really enjoy the lessons, they are the best I have found for the subject matter.
Hey thanks for the awesome feedback! You can find a full list of the software/hardware that I use at www.engineer4free.com/tools
Thank you for the video. But in first example why not connect D directly to G instead of using "dummy" because G starts when D finish as shown in the table
Hey, the nodes in this style are the points in time, whereas the arrows are the activities. Node 6 is the point in time when D is finished, and also when G begins. G does begin right when D finishes according to the diagram. The dummy that goes from 5 to 6 is there so that E and F have unique start and finish nodes compared to each other (id, don'e start and finish on the exact same nodes).The dummy allowed for the creation of node 5, which means that F finishes on node 5 rather than 6. But ultimately node 5 and 6 are the same point in time, just with a different label to help identify based on the style of this network diagram. This video is worth checking out too: www.engineer4free.com/4/introduction-to-cpm-network-diagrams
Now I get it, thank you so much for your explanations
"one single node" - nice tautology
In the first example, you drew two arrows pointing to activity (6), is that okay? Isn't it supposed to be one arrow out and one arrow in for each circle (activity)?
You can have multiple arrows out of one node (going to different nodes). You can have multiple arrows in to one node (coming from different nodes). What you cannot have is more than one arrow sharing the same beginning and end node. For example, in the first problem, look at activity D. It is the only arrow that goes specifically from node 3 to node 6. No two nodes are connected directly with more than 1 arrow between them. Does that make sense? Each activity can then be labelled uniquely by just referring to the start and finish node. We call that the ij number. Activity D's ij number is 3-6. No other activity has that number.
Engineer4Free Thank you very much. This helps a lot.
I don’t know when to use dummy
Assalamualaikum, Alhamdulillah brother , Jajakallah khairan.
what about finding critical path especially with the second example???
thank u it really help me drawing the diagram...
Thankyou So So So much Sir🙏🏾🙏🏾❤️❤️God Bless you🥰🙏🏾
Thank you🙏 I understood it well🧡
Nice one, right on!
Sir if there is a dummy activity ; do we have to put a higher number on the top of the arrow of the dummy or it doesn't matter
Every arrow should go from a smaller number to a bigger number!
Thank you, i like way of explanation and i hope you will deliver as other tutorial
Rey thanks. Yeah I did a lot of PM videos you can find them all here: engineer4free.com/project management
great video. Thanks
Glad you liked it, thanks for watching! Do check out engineer4free.com/project-management if you haven't already for all the PM videos! 👍👍
Critical path easy understand, Thank you
Very easy trick to understand.... Thanks dude👍
Thx a lot. But why you didnt connect 2 to 3 for c ? Must b a dummy activity or is it a choice to b drawn dummy???
Both are ES
Are you referring to the second diagram? It's because if we did that, then G and E would both have the same i,j numbers (be on the same arrow). We can't have that, so we need a dummy.
why do we put a dummy node in the first example? can we not make it without the dummy node?
sir you have told in previous video that each activity must have a node but here in activity E their is no node ?
This is an Activity on Arrow (AOA) diagram. Each activity (arrow) must have a unique start node and end node (no two arrows can point from the same start node to the same end node. See videos 10-12 here: engineer4free.com/project-management
wonderful explain
Thanks .very importance of Exams time
Thanks for watching! :)
I'm searching for a good software for drawing pert chart. Any idea which one we could use?
Hi there , what is the different between CPM and arrow diagram?
Hi, sorry for any confusion brought about by the naming of each style of diagram. There are two types of network diagrams: Activity on Node (AON) and Activity on Arrow (AOA). In these videos I usually refer to AON as PDM, and AOA as CPM. That's local lingo for me that I originally learned, but you are actually better to use AON and AOA, it's more clear.
great video thx!
Glad you liked it! =)
u shouldve explained dummy activities more in this video
hi sir
so we can number in any way as long as the top of the arrow has a higher number ?
Yeah, check this video too: www.engineer4free.com/4/introduction-to-cpm-network-diagrams
@@Engineer4Free ok i will
Thanx man nice job helped alot
You're welcome, glad to hear it!
Is numbering should be given sir?
Since we can make a decision where to put dummies, does that mean there is more than 1 correct answer in these type of questions?
And also can there be no dummies when drawing these?
Yes there may be more than one right answer depending on the question. Some problems may not require dummies. The right answer(s) will have the least amount of dummies. If there is a way to draw with diagram with less dummies that you have done, then you do not have the right answer. Check out videos 10-12 here: engineer4free.com/project-management
How would i handle creating this diagram if for example activity F had no predessor? I have a hw problem with this and don't really understand how an activity so far down the list can have no predessor... thanks!
All activities with no predecessors are initial activities. Put it somewhere on the far left of the diagram near A and give them both an ES of 0. If F has some successors, just draw a really long line connecting F to it’s successors. You may need to attempt the drawing a few times to reduce crossovers. It might look stupid, but is totally possible.
In the second diagram, what is the need of a dummy arrow from B to C to make G. It can be straight instead of dummy right. I am very confused. Please help
A straight arrow between two nodes represents an activity in this style of network diagram. There is no such activity present in the table of dependencies that would go between nodes 3 and 4 (if there was it would mean there would be an activity that succeeds B and is succeeded by G). The dummy activity has to be there because it shows the dependence of G on B. Node 4 is the point in time where G starts, and node 3 is the point in time when B finishes; B must be finished by the time G starts, so hence the dummy going from 3 to 4. Watch this video: ua-cam.com/video/TDriHWnHkrE/v-deo.html it is the predecessor (lol.. bad joke) to the video that we are commenting on and explains some things. These videos are all part of a larger playlist too, you can check it out at engineer4free.com/project-management this is video #11 in the course.
If you do that, E would become dependent on both B and C, which is not the case.
Hey, not sure what you mean. There is no point in the second example where the network diagram suggests that E is dependent on B and C. Can you clarify?
Oh no, i was just supporting your answer and trying to clarify it to Lucky Lucky that why we need the dummy arrow.
ahaha ok cool! Thanks for helping =)
Pls I want to ask the difference between CPM and the PERT in terms of diagram
these helps me a lot for our Projects...Thank you very much..
In cases of construction, where the next activity would start without having a predecessor end. How do make a pert cpm network for that?
Hey, I have some videos on more complcated relationships in projects, you can find them in videos 16-22 here: engineer4free.com/project-management and also some other videos on PERT which are numbers 39-46 in the same link. Should be enough to get started.
Watching day before exam
How'd it go 😅
in the second problem you can eliminate the dummy activity by replacing it with E there, right?
for the first case cant we erase the dummy totally and just point out to no 6 for D,E,F?
Thank you so much, Sir! It was of Great help
Good to know! Thanks for commenting!
thank you, sir! really
You're welcome =)
Why can't Task F connect directly to Node 6 as Task D did?
does the dummy affect the calculation when determining the critical path? please help
Dummy has 0 duration. Use it to trace dependence but do not add any time when doing the forward or backward pass if you hit a dummy.
Hi
i love your videos.... i am lost with my diagram that i must do... please assist
on my diagram i am with E been alone and not depending on anything, is that still ok?
There can be more than one initial activity. So if activities A and E of your project for example don’t have predecessors, draw them both near the left side of the diagram, and then draw their successors coming out to the right.
A - 8
B - 10
C A 7
D B 8
E B 22
F C,D 12
Thank you kindly
You're welcome!!
How do we put the numbers in the nodes didn’t understand even with watching your introduction number sir
Video*
Could you help figure this one out? Killing my brain over here.
Activity Duration Dependent on
A 3 none
C 3 none
B 2 A
D 5 C
E 2 none
F 4 E
G 3 D,F
H 1 D,F
I 2 B,G
R 0 H,I
please solve it
A -
B-
C A
D A
E C,B
F C,B
G D,E
please solve it sir.
Thank you
just a question when doing the first example i done it before you had completed it to see if i done it right like you i did essentially do it more or less right but i didnt have a dummy activity at all i just drew a curved arrow flowing into g is this acceptable or must i use a dummy activity
how do calculate the critical path then?
Thank you sir 👍
Why do activity F need to go to event 5 and it cannot go straight to event 6?
It is just a requirement of this style of network diagram that any two given nodes only have one single arrow connecting them. It gives each activity (arrow) a unique identity of which node it comes from and goes to. Because two arrows would ideally go between 4 and 6, we need to introduce the dummy node 5 so that one arrow goes from 4 to 6 and the other goes from 4 to 5.
Thank you sir
You're welcome Amit!
Hey is it possible to create network diagram without predecessor? My lecturer is retard giving me just activities and duration
There should be a table of dependencies that indicates the relationship between activities
Can you make a video with lag? SS, FF
Yes I did, see videos 18 - 22 here: engineer4free.com/project-management
Can you tell me why you need a dummy (1:55) from F -> G? Why can't it be similar to what E has where it has no dummy?
Yeah no problem. This is an Activity on Arrow network diagram, and one of the rules about these things is that only one arrow may go between two given nodes. ie, node 4 and 6 can only have one arrow connecting them directly, not two. By doing this, we can identify any given activity (arrow) by it's i-j number, and in the case of activity E, that would be 4-6. It's just the convention, so because two activities here go between nodes 4 and 6, we need to introduce the dummy activity that gets its own node (5). Either E or F could have had the dummy, but one of them needs it in this project.
Thank you!@@Engineer4Free
@@Engineer4Free HI, so whats the ij number for F 4.5.6? 4.5? 4.6?
very helpful video thnqq u
GOD BLESS YOU SIR
THANKS DUDE, i was hopeless i couldnt understand that and now it is clear as FUCK THANKS
loll your WELCOME!!
Your video is very helpful but you're very fast!
Ah yeah there is another video that I introduce the method and go a bit slower in, check it out here: engineer4free.com/4/introduction-to-cpm-network-diagrams
Hi, Brother...which swoftware are you use for making this vedio?? Please help me by answer.
Hey Mafuj. I keep a current list of the hardware and software that I use at engineer4free.com/tools Its technically all hand drawn just with the aid of a drawing tablet and some video editing tricks
great job..tnx
Thanks for watching!
Had to put this at 0.5x speed lol, you speak way too fast.
really helpful
Thanks for the comment!
What program or software are you drawing from?
It's not PM software, just hand drawn with a tablet. I've got a list of all the hardware and software I use in the videos at engineer4free.com/tools
Thank you!
thanks. very usefull
Activity on Node laugh when watch this vid especially at the dummy :'D
Yupp basically
thanku so much sir
You're welcome, thanks for watching!
Thankyou sir....
You’re welcome!!! =)
SO LOOK EAZY
AWESOME
Dude calm dowm
:p
you are too fast for beginners....
thanks for the vid but i'll look elsewhere
No problem. I'll just let you know that this video is part of a playlist though and comes after a full section on PDM network diagrams and an introductory video on CPM network diagrams. Check out the full curse at engineer4free.com/project-management I recommend watching video 10, and if you have the time, videos 1-12. They build off each other, so by the time you get to this video, you'll have sufficient exposure to this kind of stuff =)
Replace my teacher pls
haha I wish! You can at least find my full playlist here: engineer4free.com/project-management plz share with your class 🙌
Ur too fast making it hard to understand
Not really good example. Why you draw two points for one activity? This is superfluous and unnecessary actions. Why complicate if classic diagram is built with one point in one activity. Such diagram difficult to understand and harder to look.
I agree that the bottom diagram is less intuitive. However, it's a legitamite way to draw diagrams, and is taught in universities, so I have made some tutorials to help students that need to learn how it works.
@@Engineer4Free I see, yeah of course this is legitimate way.
Woah
😏
Finally I get this fucking dummy bs.
hahaha yeah it's not the most intuitive thing
PNC